<PAGE>
 
             Securities and Exchange Commission on July 16, 1997.
                                                      Registration No. 333-_____
________________________________________________________________________________
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C.  20549
                   ________________________________________

                                   FORM S-8
                            REGISTRATION STATEMENT
                                     Under
                          THE SECURITIES ACT OF 1933
                   ________________________________________

                            FRONTIER AIRLINES, INC.
            ------------------------------------------------------    
            (Exact name of registrant as specified in its charter)

         Colorado                                              84-1256945
---------------------------------                         ----------------------
(State or other jurisdiction                              (I.R.S. Employer
of incorporation or organization)                         Identification Number)

                   12015 East 46th Avenue, Denver, CO  80239
                   -----------------------------------------
             (Address of Registrant's principal executive offices)

                            FRONTIER AIRLINES, INC.
                            1994 STOCK OPTION PLAN
                            ----------------------
                           (Full title of the plan)

                                Arthur T. Voss
                            Frontier Airlines, Inc.
                            12015 East 46th Avenue
                            Denver, Colorado  80239
                                (303) 371-7400
                                --------------
           (Name, address and telephone number of agent for service)

                        CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------ 
                                             Proposed Maxi-    Proposed Maxi-
Title of Securities       Amount to Be        mum Offering      mum Aggregate      Amount of
to be Registered           Registered        Price Per Share   Offering Price   Registration Fee
------------------------------------------------------------------------------------------------
<S>                      <C>                 <C>               <C>              <C>
Common Stock             2,250,000 Shares       $3.625*        $8,156,250*         $2,471.60
------------------------------------------------------------------------------------------------
</TABLE>

*    Determined solely for the purpose of calculating the registration fee based
     on the closing bid price of shares of the Common Stock on the Nasdaq
     SmallCap Market on July 11, 1997.
________________________________________________________________________________
<PAGE>
 
                                    PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS
                     --------------------------------------

Item 3. INCORPORATION OF DOCUMENTS BY REFERENCE
        ---------------------------------------

        Frontier Airlines, Inc. (the "Company") hereby incorporates by reference
in this Registration Statement the following documents:

        (a) The Company's Annual Report on Form 10-KSB for the fiscal year ended
            March 31, 1997;

        (b) A description of the Company's Common Stock as contained in the
            Company's Registration Statement on Form 8-A as declared effective
            by the Securities and Exchange Commission on May 19, 1994; and

        (c) A description of the Company's Common Stock Purchase Rights as
            contained in the Company's Registration Statement Form 8-A as
            declared effective by the Securities and Exchange Commission on
            March 17, 1997.

        All documents subsequently filed by the Company pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934, as amended,
which documents shall be deemed incorporated by reference in this Registration
Statement as a part hereof from the date of filing such documents until a post-
effective amendment to this Registration Statement is filed which indicates that
all shares of Common Stock being offered hereby have been sold or which
deregisters all shares of Common Stock then remaining unsold.

Item 4. DESCRIPTION OF SECURITIES
        -------------------------

        Not Applicable.

Item 5. INTERESTS OF NAMED EXPERTS AND COUNSEL
        --------------------------------------

        Not Applicable.

Item 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS
        -----------------------------------------

        The Company's Bylaws require the Company to indemnify, to the fullest
extent authorized by applicable law, any person who is or is threatened to be
made a party to any civil, criminal, administrative, investigative, or other
action or proceeding instituted or threatened by reason of the fact that he is
or was a director or officer of the Company or is or was serving at the request
of the Company as a director or officer or another corporation, partnership,
joint venture, trust or other enterprise.

        The Company's Articles of Incorporation provide that, to the fullest
extent permitted by the Colorado Business Corporation Act, directors and
officers of the Company shall not be liable to the Company or any of its
shareholders for damages caused by a breach of a fiduciary duty by such
directors or officers.

        Sections 7-109-101 through 7-109-110 of the Colorado Business
Corporation Act authorize the indemnification of directors and officers against
liability incurred by reason of being a director or officer and against expenses
(including attorney's fees), judgments, fines and amounts paid in settlement and
reasonably incurred in connection with any action seeking to establish such
liability, in the case of third-party claims, if the officer or director acted
in good faith and in a manner he reasonably believed to be in or not opposed to
the best

                                      -2-
<PAGE>
 
interests of the corporation, and in the case of actions by or in the right of
the corporation, if the officer or director acted in good faith and in a manner
he reasonably believed to be in the or not opposed to the best interests of the
corporation and if such officer or director shall not have been adjudged liable
to the corporation, unless a court otherwise determines.  Indemnification is
also authorized with respect to any criminal action or proceeding where the
officer or director also had no reasonable cause to believe his conduct was
unlawful.

        The above discussion of the Company's Articles of Incorporation, Bylaws
and the Colorado Business Corporation Act is only a summary and is qualified in
its entirety by the full text of each of the foregoing.

Item 7. EXEMPTION FROM REGISTRATION CLAIMED
        -----------------------------------

        Not Applicable.

Item 8. EXHIBITS
        --------

        3.1   Articles of Incorporation of the Company /(1)/

        3.2   Amended Bylaws of the Company/(2)/
 
        5.1*  Opinion of Parcel, Mauro, Hultin & Spaanstra, P.C. as to the
              legality of the Company's Common Stock being registered.

        23.1* Consent of KPMG Peat Marwick LLP.
_________________________

        *     Filed herewith.

        /(1)/  Incorporated by reference from Exhibit 3.1 to the Company's
Registration Statement on Form SB-2, Registration No. 33-77790.

        /(2)/  Incorporated by reference from Exhibit 3.2 to the Company's Form
10-KSB for the fiscal year ended March 31, 1997, File No. 0-24126.

Item 9. UNDERTAKINGS
        ------------

        The Company hereby undertakes:

        (1) To file, during any period in which offers or sales are being made,
a post-effective amendment to this registration statement: (i) to include any
prospectus required by Section 10(a)(3) of the Securities Act; (ii) to reflect
in the prospectus any facts or events which, individually or together, represent
a fundamental change in the information in the registration statement; and (iii)
to include any additional or changed material information on the plan of
distribution.

        (2) That, for the purpose of determining any liability under the
Securities Act each post-effective amendment shall be treated as a new
registration statement relating to the securities offered, and the offering of
such securities at that time shall be treated as the initial bona fide offering
thereof.

        (3) To file a post-effective amendment to remove from registration any
of the securities that remain unsold at the end of the offering.

                                      -3-
<PAGE>
 
        (4) That, for purposes of determining any liability under the Securities
Act, each filing of the Company's annual report pursuant to section 13(a) or
section 15(d) of the Exchange Act (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to section 15(d) of the Exchange
Act) that is incorporated by reference in the registration statement shall be
deemed to be a new registration statement relating to the securities offered
therein, and the offering of such securities at that time shall be deemed to be
the initial bona fide offering thereof.

        (5) That, insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and controlling
persons of the Company pursuant to the foregoing provisions, or otherwise, the
Company has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the
Securities Act and is, therefore, unenforceable.  In the event that a claim for
indemnification against such liabilities (other than the payment by the Company
of expenses incurred or paid by a director, officer or controlling person of the
Company in the successful defense of any action, suit or proceeding) is asserted
by such director, officer or controlling person in connection with the
securities being registered, the Company will, unless in the opinion of its
counsel the matter has been settled by controlling precedent, submit to a court
of appropriate jurisdiction the question whether such indemnification by it is
against public policy as expressed in the Securities Act and will be governed by
the final adjudication of such issue.

                                      -4-
<PAGE>
 
                                  SIGNATURES
                                  ----------

     Pursuant to the requirements of the Securities Act of 1933, the Company
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8, and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Denver, State of Colorado on July 14, 1997.

                                         FRONTIER AIRLINES, INC.

                                         By: /s/ Samuel D. Addoms
                                            ----------------------------------
                                            Samuel D. Addoms
                                            Principal Executive Officer and
                                            Principal Financial Officer


                                         By: /s/ Elissa A. Potucek
                                            ----------------------------------
                                            Elissa A. Potucek
                                            Controller and Principal
                                            Accounting Officer

     Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.


Date:      July 14, 1997                 By: /s/ Samuel D. Addoms
                                            --------------------------
                                            Samuel D. Addoms, Director


Date:      July 14, 1997                 By: /s/ D. Dale Browning
                                            --------------------------
                                            D. Dale Browning, Director


Date:     July 14, 1997                  By: /s/ William B. McNamara
                                            -----------------------------
                                            William B. McNamara, Director


Date:                                    By:
                                            ---------------------------
                                            B. LaRae Orullian, Director


Date:     July 14, 1997                  By: /s/ Paul Stephen Dempsey
                                            ------------------------------
                                            Paul Stephen Dempsey, Director

                                      -5-
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 13262}]
{"company-data": {"conformed-name": "FRONTIER AIRLINES INC /CO/", "cik": "0000921929", "assigned-sic": "4512", "irs-number": "841256945", "state-of-incorporation": "CO", "fiscal-year-end": "0331"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-31389", "film-number": "97641465"}, "business-address": {"street1": "12015 EAST 46TH AVE", "city": "DENVER", "state": "CO", "zip": "80239", "phone": "3033717400"}}
Securities and Exchange Commission on July 16, 1997.
                                                      Registration No. 333-_____
________________________________________________________________________________
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C.  20549
                   ________________________________________

                                   FORM S-8
                            REGISTRATION STATEMENT
                                     Under
                          THE SECURITIES ACT OF 1933
                   ________________________________________

                            FRONTIER AIRLINES, INC.
            ------------------------------------------------------    
            (Exact name of registrant as specified in its charter)

         Colorado                                              84-1256945
---------------------------------                         ----------------------
(State or other jurisdiction                              (I.R.S. Employer
of incorporation or organization)                         Identification Number)

                   12015 East 46th Avenue, Denver, CO  80239
                   -----------------------------------------
             (Address of Registrant's principal executive offices)

                            FRONTIER AIRLINES, INC.
                            1994 STOCK OPTION PLAN
                            ----------------------
                           (Full title of the plan)

                                Arthur T. Voss
                            Frontier Airlines, Inc.
                            12015 East 46th Avenue
                            Denver, Colorado  80239
                                (303) 371-7400
                                --------------
           (Name, address and telephone number of agent for service)

                        CALCULATION OF REGISTRATION FEE
------------------------------------------------------------------------------------------------ 
                                             Proposed Maxi-    Proposed Maxi-
Title of Securities       Amount to Be        mum Offering      mum Aggregate      Amount of
to be Registered           Registered        Price Per Share   Offering Price   Registration Fee
------------------------------------------------------------------------------------------------
Common Stock             2,250,000 Shares       $3.625*        $8,156,250*         $2,471.60
------------------------------------------------------------------------------------------------
*    Determined solely for the purpose of calculating the registration fee based
     on the closing bid price of shares of the Common Stock on the Nasdaq
     SmallCap Market on July 11, 1997.
________________________________________________________________________________
PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS
                     --------------------------------------

Item 3. INCORPORATION OF DOCUMENTS BY REFERENCE
        ---------------------------------------

        Frontier Airlines, Inc. (the "Company") hereby incorporates by reference
in this Registration Statement the following documents:

        (a) The Company's Annual Report on Form 10-KSB for the fiscal year ended
            March 31, 1997;

        (b) A description of the Company's Common Stock as contained in the
            Company's Registration Statement on Form 8-A as declared effective
            by the Securities and Exchange Commission on May 19, 1994; and

        (c) A description of the Company's Common Stock Purchase Rights as
            contained in the Company's Registration Statement Form 8-A as
            declared effective by the Securities and Exchange Commission on
            March 17, 1997.

        All documents subsequently filed by the Company pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934, as amended,
which documents shall be deemed incorporated by reference in this Registration
Statement as a part hereof from the date of filing such documents until a post-
effective amendment to this Registration Statement is filed which indicates that
all shares of Common Stock being offered hereby have been sold or which
deregisters all shares of Common Stock then remaining unsold.

Item 4. DESCRIPTION OF SECURITIES
        -------------------------

        Not Applicable.

Item 5. INTERESTS OF NAMED EXPERTS AND COUNSEL
        --------------------------------------

        Not Applicable.

Item 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS
        -----------------------------------------

        The Company's Bylaws require the Company to indemnify, to the fullest
extent authorized by applicable law, any person who is or is threatened to be
made a party to any civil, criminal, administrative, investigative, or other
action or proceeding instituted or threatened by reason of the fact that he is
or was a director or officer of the Company or is or was serving at the request
of the Company as a director or officer or another corporation, partnership,
joint venture, trust or other enterprise.

        The Company's Articles of Incorporation provide that, to the fullest
extent permitted by the Colorado Business Corporation Act, directors and
officers of the Company shall not be liable to the Company or any of its
shareholders for damages caused by a breach of a fiduciary duty by such
directors or officers.

        Sections 7-109-101 through 7-109-110 of the Colorado Business
Corporation Act authorize the indemnification of directors and officers against
liability incurred by reason of being a director or officer and against expenses
(including attorney's fees), judgments, fines and amounts paid in settlement and
reasonably incurred in connection with any action seeking to establish such
liability, in the case of third-party claims, if the officer or director acted
in good faith and in a manner he reasonably believed to be in or not opposed to
the best

                                      -2-
interests of the corporation, and in the case of actions by or in the right of
the corporation, if the officer or director acted in good faith and in a manner
he reasonably believed to be in the or not opposed to the best interests of the
corporation and if such officer or director shall not have been adjudged liable
to the corporation, unless a court otherwise determines.  Indemnification is
also authorized with respect to any criminal action or proceeding where the
officer or director also had no reasonable cause to believe his conduct was
unlawful.

        The above discussion of the Company's Articles of Incorporation, Bylaws
and the Colorado Business Corporation Act is only a summary and is qualified in
its entirety by the full text of each of the foregoing.

Item 7. EXEMPTION FROM REGISTRATION CLAIMED
        -----------------------------------

        Not Applicable.

Item 8. EXHIBITS
        --------

        3.1   Articles of Incorporation of the Company /(1)/

        3.2   Amended Bylaws of the Company/(2)/
 
        5.1*  Opinion of Parcel, Mauro, Hultin & Spaanstra, P.C. as to the
              legality of the Company's Common Stock being registered.

        23.1* Consent of KPMG Peat Marwick LLP.
_________________________

        *     Filed herewith.

        /(1)/  Incorporated by reference from Exhibit 3.1 to the Company's
Registration Statement on Form SB-2, Registration No. 33-77790.

        /(2)/  Incorporated by reference from Exhibit 3.2 to the Company's Form
10-KSB for the fiscal year ended March 31, 1997, File No. 0-24126.

Item 9. UNDERTAKINGS
        ------------

        The Company hereby undertakes:

        (1) To file, during any period in which offers or sales are being made,
a post-effective amendment to this registration statement: (i) to include any
prospectus required by Section 10(a)(3) of the Securities Act; (ii) to reflect
in the prospectus any facts or events which, individually or together, represent
a fundamental change in the information in the registration statement; and (iii)
to include any additional or changed material information on the plan of
distribution.

        (2) That, for the purpose of determining any liability under the
Securities Act each post-effective amendment shall be treated as a new
registration statement relating to the securities offered, and the offering of
such securities at that time shall be treated as the initial bona fide offering
thereof.

        (3) To file a post-effective amendment to remove from registration any
of the securities that remain unsold at the end of the offering.

                                      -3-
(4) That, for purposes of determining any liability under the Securities
Act, each filing of the Company's annual report pursuant to section 13(a) or
section 15(d) of the Exchange Act (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to section 15(d) of the Exchange
Act) that is incorporated by reference in the registration statement shall be
deemed to be a new registration statement relating to the securities offered
therein, and the offering of such securities at that time shall be deemed to be
the initial bona fide offering thereof.

        (5) That, insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and controlling
persons of the Company pursuant to the foregoing provisions, or otherwise, the
Company has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the
Securities Act and is, therefore, unenforceable.  In the event that a claim for
indemnification against such liabilities (other than the payment by the Company
of expenses incurred or paid by a director, officer or controlling person of the
Company in the successful defense of any action, suit or proceeding) is asserted
by such director, officer or controlling person in connection with the
securities being registered, the Company will, unless in the opinion of its
counsel the matter has been settled by controlling precedent, submit to a court
of appropriate jurisdiction the question whether such indemnification by it is
against public policy as expressed in the Securities Act and will be governed by
the final adjudication of such issue.

                                      -4-
SIGNATURES
                                  ----------

     Pursuant to the requirements of the Securities Act of 1933, the Company
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8, and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Denver, State of Colorado on July 14, 1997.

                                         FRONTIER AIRLINES, INC.

                                         By: /s/ Samuel D. Addoms
                                            ----------------------------------
                                            Samuel D. Addoms
                                            Principal Executive Officer and
                                            Principal Financial Officer

                                         By: /s/ Elissa A. Potucek
                                            ----------------------------------
                                            Elissa A. Potucek
                                            Controller and Principal
                                            Accounting Officer

     Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.

Date:      July 14, 1997                 By: /s/ Samuel D. Addoms
                                            --------------------------
                                            Samuel D. Addoms, Director

Date:      July 14, 1997                 By: /s/ D. Dale Browning
                                            --------------------------
                                            D. Dale Browning, Director

Date:     July 14, 1997                  By: /s/ William B. McNamara
                                            -----------------------------
                                            William B. McNamara, Director

Date:                                    By:
                                            ---------------------------
                                            B. LaRae Orullian, Director

Date:     July 14, 1997                  By: /s/ Paul Stephen Dempsey
                                            ------------------------------
                                            Paul Stephen Dempsey, Director

                                      -5-