EX-4.3


 Exhibit 4.3 

EXECUTION VERSION 
 TRUST
SUPPLEMENT NO. 2017-1A 
 Dated as of November 28, 2017 

between 
 SPIRIT AIRLINES, INC.

 and 
 WILMINGTON
TRUST, NATIONAL ASSOCIATION, 
 as Trustee, 

To 
 PASS THROUGH TRUST
AGREEMENT 
 Dated as of August 11, 2015 

Spirit Airlines Pass Through Trust 2017-1A 

Spirit Airlines Pass Through Certificates, 

Series 2017-1A 

  
 Trust Supplement No.
2017-1A 
 (Spirit 2017-1 EETC) 







 Table of Contents 

 

							
	 	  	 	  	Page	 
	Article I DEFINITIONS	  	 	2	 
	Section 1.01	  	Definitions	  	 	2	 
		
	Article II DECLARATION OF TRUST	  	 	8	 
	Section 2.01	  	Declaration of Trust	  	 	8	 
	Section 2.02	  	Permitted Activities	  	 	8	 
		
	Article III THE CERTIFICATES	  	 	8	 
	Section 3.01	  	The Certificates	  	 	8	 
	Section 3.02	  	Terms and Conditions	  	 	8	 
		
	Article IV ISSUANCE AND TRANSFER OF THE CLASS A CERTIFICATES	  	 	11	 
	Section 4.01	  	Issuance of Class A Certificates	  	 	11	 
	Section 4.02	  	Legends	  	 	11	 
	Section 4.03	  	Book-Entry Provisions for Global Certificates	  	 	12	 
		
	Article V DISTRIBUTION; STATEMENTS TO CERTIFICATEHOLDERS	  	 	14	 
	Section 5.01	  	Statements to Certificateholders	  	 	14	 
		
	Article VI DEFAULT	  	 	15	 
	Section 6.01	  	Purchase Rights of Certificateholders	  	 	15	 
		
	Article VII THE TRUSTEE	  	 	18	 
	Section 7.01	  	Delivery of Documents; Delivery Dates	  	 	18	 
	Section 7.02	  	Withdrawal of Deposits	  	 	20	 
	Section 7.03	  	The Trustee	  	 	20	 
	Section 7.04	  	Representations and Warranties of the Trustee	  	 	20	 
	Section 7.05	  	Trustee Liens	  	 	21	 
		
	Article VIII ADDITIONAL AMENDMENT; SUPPLEMENTAL AGREEMENTS	  	 	21	 
	Section 8.01	  	Amendment of Sections 5.02, 6.07, 7.09, 8.04, 9.01, 12.01 and 12.02 of the Basic Agreement	  	 	21	 
	Section 8.02	  	Supplemental Agreements Without Consent of Class A Certificateholders	  	 	21	 
	Section 8.03	  	Supplemental Agreements with Consent of Class A Certificateholders	  	 	22	 
	Section 8.04	  	Consent of Trustees for Amendment of Section 6.01	  	 	23	 
	Section 8.05	  	Notice to Rating Agencies	  	 	23	 
		
	Article IX MISCELLANEOUS PROVISIONS	  	 	23	 
	Section 9.01	  	Final Termination Date	  	 	23	 
	Section 9.02	  	Basic Agreement Ratified	  	 	23	 
	Section 9.03	  	Governing Law	  	 	23	 
	Section 9.04	  	Counterparts	  	 	23	 
	Section 9.05	  	Intention of Parties	  	 	23	 
	Section 9.06	  	Submission to Jurisdiction	  	 	24	 
	Section 9.07	  	Successor and Assigns	  	 	24	 
	Section 9.08	  	Normal Commercial Relations	  	 	24	 
	Section 9.09	  	No Recourse against Others	  	 	24	 

 EXHIBITS 

					
	 Exhibit A
	  	-	  	 Form of Certificate

	 Exhibit B
	  	-	  	 DTC Letter of Representations

	 Exhibit C
	  	-	  	Amendments to Basic Agreement


  

					
		  	i	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)










					
	 	  	 	  	Page

 SCHEDULES 

					
	 Schedule I
	  	-	  	 Series A Equipment Notes, Principal Amounts, Maturities and Aircraft

	 Schedule II
	  	-	  	 Note Documents



  

					
		  	ii	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 TRUST SUPPLEMENT NO. 2017-1A 

This TRUST SUPPLEMENT NO. 2017-1A, dated as of November 28, 2017, 2017 (as amended from time
to time, the “Trust Supplement”), between SPIRIT AIRLINES, INC., a Delaware corporation (together with any successor in interest pursuant to Section 5.02 of the Basic Agreement, the “Company” or “Spirit”), and
WILMINGTON TRUST, NATIONAL ASSOCIATION, a national banking association, as trustee (together with any successor in interest and any successor or other trustee appointed as provided in the Basic Agreement, the “Trustee”) under the Pass
Through Trust Agreement, dated as of August 11, 2015, between the Company and Wilmington Trust, National Association (the “Basic Agreement”). 

W I T N E S S E T H: 

WHEREAS, the Basic Agreement, which is unlimited as to the aggregate face amount of Certificates that may be issued and authenticated
thereunder, has heretofore been executed and delivered; 
 WHEREAS, Spirit has obtained commitments from Airbus S.A.S. for the delivery
scheduled on or prior to October 31, 2018 of the 12 aircraft described in Schedule I (the “Aircraft”), and Spirit wishes to finance the Aircraft pursuant to the NPA; 

WHEREAS, pursuant to each Indenture, Spirit will issue on a recourse basis three series of Equipment Notes secured by the related Aircraft and
may issue one or more series of Additional Equipment Notes and one or more series of Refinancing Equipment Notes; 
 WHEREAS, the Trustee
shall hereby declare the creation of the Class A Trust (as defined below) for the benefit of Holders of the Class A Certificates (as defined below) to be issued in respect of such Class A Trust, and the initial Holders of the
Class A Certificates, as grantors of such Class A Trust, by their respective acceptances of the Class A Certificates, shall join in the creation of the Class A Trust with the Trustee; 

WHEREAS, all Certificates to be issued by the Class A Trust will evidence Fractional Undivided Interests in the Class A Trust and
will have no rights, benefits or interests in respect of any other separate Trust or the property held therein; 
 WHEREAS, the Escrow Agent
and the Underwriters have contemporaneously herewith entered into an Escrow Agreement with the Escrow Paying Agent pursuant to which the Underwriters will deliver to the Escrow Agent the proceeds from the sale of the Class A Certificates, and
have irrevocably instructed the Escrow Agent to withdraw and pay funds from such proceeds upon request and proper certification by the Trustee to purchase Series A Equipment Notes pursuant to the NPA and the applicable Participation Agreements from
time to time prior to the Delivery Period Termination Date; 
 WHEREAS, the Escrow Agent on behalf of the Class A Certificateholders
has contemporaneously herewith entered into a Deposit Agreement with the Depositary under which the Deposits referred to therein will be made and from which Deposits it will withdraw funds to allow the Trustee to purchase Series A Equipment Notes
from time to time prior to the Delivery Period Termination Date; 
 WHEREAS, pursuant to the terms and conditions of the Basic Agreement, as
supplemented by this Trust Supplement, the NPA and the Participation Agreements, the Trustee on behalf of the Class A Trust shall from time to time purchase the Series A Equipment Notes issued by the Company pursuant to the Indentures relating
to the Aircraft having the identical interest rate as, and final maturity dates not later than the final Regular Distribution Date of, the Class A Certificates issued hereunder and shall hold such Series A Equipment Notes in trust for the
benefit of the Class A Certificateholders; 

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 WHEREAS, pursuant to the terms and conditions of the Intercreditor Agreement referred to in
Section 3.02(i) hereof, the Trustee and the other parties thereto will agree to the terms of subordination set forth therein; 

WHEREAS, all of the conditions and requirements necessary to make this Trust Supplement, when duly executed and delivered, a valid, binding
and legal instrument in accordance with its terms and for the purposes herein expressed, have been done, performed and fulfilled, and the execution and delivery of this Trust Supplement in the form and with the terms hereof have been in all respects
duly authorized; 
 WHEREAS, the Basic Agreement, as supplemented by this Trust Supplement, is subject to the provisions of the Trust
Indenture Act and shall, to the extent applicable, be governed by such provisions; 
 NOW, THEREFORE, in consideration of the mutual
agreements herein contained, and of other good and valuable consideration the receipt and adequacy of which are hereby acknowledged, the parties hereto agree as follows: 

ARTICLE I 
 DEFINITIONS

 Section 1.01 Definitions. Unless otherwise specified herein or the context otherwise requires, capitalized terms used but
not defined herein, including in the recitals hereto, shall have the respective meanings set forth, and shall be construed and interpreted in the manner described, in the Basic Agreement. As used herein, the term “Agreement” shall mean the
Basic Agreement, as supplemented by this Trust Supplement. For all purposes of the Basic Agreement as supplemented by this Trust Supplement, the following capitalized terms have the following meanings (any term used herein which is defined in both
this Trust Supplement and the Basic Agreement shall have the meaning assigned thereto in this Trust Supplement for purposes of the Basic Agreement as supplemented by this Trust Supplement). 

Account: Has the meaning specified in the Deposit Agreement. 

Additional Certificateholder: Has the meaning specified in the Intercreditor Agreement. 

Additional Certificates: Has the meaning specified in the Intercreditor Agreement. 

Additional Equipment Notes: Has the meaning specified in the Intercreditor Agreement. 

Additional Trust: Has the meaning specified in the Intercreditor Agreement. 

Additional Trust Agreement: Has the meaning specified in the Intercreditor Agreement. 

Affiliate: Has the meaning specified in the Intercreditor Agreement. 

Agreement: Has the meaning specified in the first paragraph of Section 1.01 of this Trust Supplement. 

Aircraft: Has the meaning specified in the recitals to this Trust Supplement and any Replacement Aircraft (as defined in
the applicable Indenture) in replacement thereof in accordance with the applicable Indenture. 
 Applicable Funding
Date: Has the meaning specified in Section 7.01(b) of this Trust Supplement. 

  

					
		  	2	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 Applicable Notice of Purchase Withdrawal: Has the meaning specified in the
Escrow Agreement. 
 Applicable Participation Agreement: Has the meaning specified in Section 7.01(b) of this
Trust Supplement. 
 Basic Agreement: Has the meaning specified in the preamble to this Trust Supplement. 

Business Day: Has the meaning specified in the Intercreditor Agreement. 

Certificate: Means a Class AA Certificate, a Class A Certificate or a Class B Certificate, as applicable.

 Certificate Buy-Out Event: Has the meaning specified in the Intercreditor
Agreement. 
 Certificateholder: Means, with respect to any Class of Certificates, the Person in whose name a
Certificate is registered in the Register for the Certificates of such Class. 
 Class: Has the meaning specified in
the Intercreditor Agreement. 
 Class AA Certificateholder: Has the meaning specified in the
Intercreditor Agreement. 
 Class AA Certificates: Has the meaning specified in the Intercreditor
Agreement. 
 Class AA Trust: Has the meaning specified in the Intercreditor Agreement. 

Class AA Trust Agreement: Has the meaning specified in the Intercreditor Agreement. 

Class AA Trustee: Has the meaning specified in the Intercreditor Agreement. 

Class A Certificateholder: Means, at any time, any Certificateholder of one or more Class A
Certificates. 
 Class A Certificates: Has the meaning specified in Section 3.01 of this Trust
Supplement. 
 Class A Liquidity Facility: Has the meaning specified in the Intercreditor
Agreement. 
 Class A Liquidity Provider: Has the meaning specified in the Intercreditor Agreement.

 Class A Trust: Has the meaning specified in Section 2.01 of this Trust Supplement. 

Class B Certificateholder: Has the meaning specified in the Intercreditor Agreement. 

Class B Certificates: Has the meaning specified in the Intercreditor Agreement. 

Class B Trust: Has the meaning specified in the Intercreditor Agreement. 

Class B Trust Agreement: Has the meaning specified in the Intercreditor Agreement. 

Class B Trustee: Has the meaning specified in the Intercreditor Agreement. 

Code: Means the Internal Revenue Code of 1986, as amended. 

Company: Has the meaning specified in the preamble to this Trust Supplement. 

Corporate Trust Office: Has the meaning specified in the Intercreditor Agreement. 

  

					
		  	3	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 Cut-off Date: Has the meaning
specified in Section 3.02(b) of this Trust Supplement. 
 Definitive Certificates: Has the meaning specified in
Section 4.01(e) of this Trust Supplement. 
 Delivery Period Termination Date: Has the meaning specified in the
NPA. 
 Deposit Agreement: Means, subject to Section 5 of the NPA, the Deposit Agreement (Class A), dated as of
the date hereof, relating to the Class A Certificates between the Depositary and the Escrow Agent, as the same may be amended, supplemented or otherwise modified from time to time in accordance with its terms. 

Depositary: Means, subject to Section 5 of the NPA, Citibank, N.A. 

Deposits: Has the meaning specified in the Deposit Agreement. 

Distribution Date: Means a Regular Distribution Date or a Special Distribution Date. 

DTC: Has the meaning specified in Section 3.02(f) of this Trust Supplement. 

DTC Participants: Has the meaning specified in Section 4.01(b) of this Trust Supplement. 

Equipment Notes: Has the meaning specified in the Intercreditor Agreement. 

ERISA: Means the Employee Retirement Income Security Act of 1974, as amended. 

ERISA Plan: Means (i) a retirement plan or other employee benefit plan or arrangement, including for this purpose an individual
retirement account, annuity or Keogh plan, that is subject to Title I of ERISA or Section 4975 of the Code or (ii) any other entity whose underlying assets are deemed to include the assets of any plan or arrangement described in
(i) above by virtue of the U.S. Department of Labor regulation in 29 CFR §2510.3-101, as modified by Section 3(42) of ERISA (or any successor to such regulation). 

Escrow Agent: Means, initially, Wilmington Trust Company, a Delaware trust company, and any replacement or successor
therefor appointed in accordance with the Escrow Agreement. 
 Escrow Agreement: Means the Escrow and Paying Agent
Agreement (Class A), dated as of the date hereof, relating to the Class A Certificates, among the Escrow Agent, the Escrow Paying Agent, the Trustee and the Underwriters, as the same may be amended, supplemented or otherwise modified from time
to time in accordance with its terms. 
 Escrow Paying Agent: Means the “Paying Agent” as defined in the
Escrow Agreement. 
 Escrow Period Termination Date: Has the meaning specified in Section 5.01(c)(i) of this
Trust Supplement. 
 Escrow Receipt: Means a receipt substantially in the form annexed to the Escrow Agreement
representing a fractional undivided interest in the funds held in escrow thereunder. 
 Event of Default: With respect
to any Indenture, has the meaning specified in Section 4.01 of such Indenture. 
 Event of Loss Withdrawal: Has
the meaning specified in the Escrow Agreement. 
 Final Withdrawal: Has the meaning specified in the Escrow Agreement.


  

					
		  	4	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 Final Withdrawal Date: Has the meaning specified in the Escrow Agreement.

 Fractional Undivided Interests: Has the meaning specified in the Intercreditor Agreement. 

Funding Date: Has the meaning specified in the NPA. 

Funding Notice: Has the meaning specified in the NPA. 

Global Certificate: Has the meaning specified in Section 4.01(b) of this Trust Supplement. 

Holder: Means a Certificateholder. 

Indenture: Has the meaning specified in the Intercreditor Agreement. 

Indirect Participants: Has the meaning specified in Section 4.01(b) of this Trust Supplement. 

Intercreditor Agreement: Has the meaning specified in Section 3.02(i) of this Trust Supplement. 

Issuance Date: Has the meaning specified in Section 7.01(a) of this Trust Supplement. 

Junior Additional Certificateholder: Means, with respect to any Additional Certificateholder exercising its right to
purchase Certificates under Section 6.01 of this Trust Supplement, any holder of any class of Additional Certificates that rank junior, in priority of payment of “Expected Distributions” for such class under the Intercreditor
Agreement, to the class of Additional Certificates held by such Additional Certificateholder. 
 Liquidity Provider:
Has the meaning specified in the Intercreditor Agreement. 
 Loan Trustee: Means, with respect to any Indenture, the
bank, trust company or other financial institution designated as loan trustee thereunder, and any successor to such loan trustee. 

Note Documents: Means, collectively, the Participation Agreements, the Indentures, each Indenture Supplement (as defined
in any Indenture), the Airframe Warranties Agreement (as defined in any Indenture) and the Equipment Notes. 
 Notice of
Purchase Withdrawal: Has the meaning specified in the Deposit Agreement. 
 NPA: Means the Note Purchase
Agreement, dated as of the date hereof, among the Trustee, the Class AA Trustee, the Class B Trustee, the Company, the Escrow Agent, the Escrow Paying Agent and the Subordination Agent, providing for, among other things, the purchase of
Series A Equipment Notes by the Trustee on behalf of the Class A Trust, as the same may be amended, supplemented or otherwise modified from time to time, in accordance with its terms. 

Operative Agreements: Has the meaning specified in the Intercreditor Agreement. 

Other Agreements: Means (i) the Class AA Trust Agreement, (ii) the Class B Trust Agreement,
(iii) any Additional Trust Agreement and (iv) any Refinancing Trust Agreement. 
 Other Trustees: Means the
trustees under the Other Agreements, and any successor or other trustee appointed as provided therein. 

  

					
		  	5	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 Other Trusts: Means the Class AA Trust, the Class B Trust, any
Additional Trust or Trusts, or any Refinancing Trust or Trusts, in each case created by the applicable Other Agreement. 

Participation Agreement: Has the meaning specified in the Intercreditor Agreement. 

Paying Agent: Means, with respect to the Class A Certificates, the paying agent maintained and appointed for such
Class A Certificates pursuant to Section 7.12 of the Basic Agreement. 
 Person: Means any individual,
corporation, limited liability company, partnership, joint venture, association, joint-stock company, trust, trustee, unincorporated organization or government or any agency or political subdivision thereof. 

Plan: Means (i) an ERISA Plan or (ii) such a plan or arrangement which is a foreign, church or governmental
plan or arrangement exempt from Title I of ERISA and Section 4975 of the Code but subject to a Similar Law. 
 Pool
Balance: Means, as of any date, (i) the original aggregate face amount of the Class A Certificates less (ii) the aggregate amount of all distributions made as of such date in respect of the Class A Certificates or in respect
of Deposits other than distributions made in respect of interest or Premium or reimbursement of any costs or expenses incurred in connection therewith. The Pool Balance as of any date shall be computed after giving effect to any distribution with
respect to unused Deposits, the payment of principal, if any, of the Series A Equipment Notes or payment with respect to other Trust Property and the distribution thereof to be made on such date. 

Pool Factor: Means, as of any Distribution Date, the quotient (rounded to the seventh decimal place) computed by
dividing (i) the Pool Balance by (ii) the original aggregate face amount of the Class A Certificates. The Pool Factor as of any Distribution Date shall be computed after giving effect to any distribution with respect to unused
Deposits, payment of principal, if any, of the Series A Equipment Notes or payment with respect to other Trust Property and the distribution thereof to be made on that date. 

Premium: Has the meaning specified in the Intercreditor Agreement. 

Prospectus Supplement: Means the final prospectus supplement, dated November 13, 2017, relating to the offering of
the Certificates. 
 Rating Agencies: Has the meaning specified in the Intercreditor Agreement. 

Refinancing Certificateholder: Has the meaning specified in the Intercreditor Agreement. 

Refinancing Certificates: Has the meaning specified in the Intercreditor Agreement. 

Refinancing Equipment Notes: Has the meaning specified in the Intercreditor Agreement. 

Refinancing Trust: Has the meaning specified in the Intercreditor Agreement. 

Refinancing Trust Agreement: Has the meaning specified in the Intercreditor Agreement. 

Regular Distribution Date: Has the meaning specified in Section 3.02(c) of this Trust Supplement. 

  

					
		  	6	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 Replacement Deposit Agreement: Has the meaning specified in the NPA. 

Replacement Depositary: Has the meaning specified in the NPA. 

Replacement Liquidity Facility: Has the meaning specified in the Intercreditor Agreement. 

Replacement Liquidity Provider: Has the meaning specified in the Intercreditor Agreement. 

Responsible Officer: Has the meaning specified in the Intercreditor Agreement. 

Scheduled Payment: Has the meaning specified in the Intercreditor Agreement. 

Securities Act: Means the Securities Act of 1933, as amended. 

Series A Equipment Notes: Has the meaning specified in the Intercreditor Agreement. 

Similar Law: Means a foreign, federal, state, or local law which is substantially similar to the prohibited transaction
provisions of Title I of ERISA or Section 4975 of the Code. 
 Special Distribution Date: Means, with respect to
the Class A Certificates, each date on which a Special Payment is to be distributed as specified in this Agreement. 

Special Payment: Means any payment (other than a Scheduled Payment) in respect of, or any proceeds of, any Equipment
Note or the Collateral (as defined in any Indenture). 
 Special Payments Account: Means, with respect to the
Class A Certificates, the account or accounts created and maintained for such series pursuant to Section 4.01(b) of the Basic Agreement (as modified by Section 7.01(c) of this Trust Supplement) and this Trust Supplement. 

Spirit: Has the meaning specified in the preamble to this Trust Supplement. 

Subordination Agent: Has the meaning specified in the Intercreditor Agreement. 

Triggering Event: Has the meaning specified in the Intercreditor Agreement. 

Trust: Means the Class AA Trust, the Class A Trust or the Class B Trust, as applicable. 

Trust Indenture Act: Means the Trust Indenture Act of 1939, as amended. 

Trust Property: Means (i) subject to the Intercreditor Agreement, the Series A Equipment Notes held as the property
of the Class A Trust, all monies at any time paid thereon and all monies due and to become due thereunder, (ii) funds from time to time deposited in the Certificate Account and the Special Payments Account and, subject to the Intercreditor
Agreement, any proceeds from the sale by the Trustee pursuant to Article VI of the Basic Agreement of any Equipment Notes and (iii) all rights of the Class A Trust and the Trustee, on behalf of the Class A Trust, under the
Intercreditor Agreement, the Escrow Agreement, the NPA and the Class A Liquidity Facility, including, without limitation, all rights to receive certain payments thereunder, and all monies paid to the Trustee on behalf of the Class A Trust
pursuant to the Intercreditor Agreement or the Class A Liquidity Facility, provided that rights with respect to the Deposits or under the Escrow Agreement, except for the right to direct withdrawals for the purchase of Series A Equipment
Notes to be held herein, will not constitute Trust Property. 
 Trust Supplement: Has the meaning specified in the
preamble hereto. 

  

					
		  	7	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 Trustee: Has the meaning specified in the preamble to this Trust
Supplement. 
 Underwriters: Means Citigroup Global Markets, Inc., Morgan Stanley & Co. LLC, Goldman
Sachs & Co. LLC and Barclays Capital Inc. 
 Underwriting Agreement: Means the Underwriting Agreement, dated
November 13, 2017, among the Underwriters and the Company, as the same may be amended, supplemented or otherwise modified from time to time in accordance with its terms. 

Withdrawal Certificate: Has the meaning specified in the Escrow Agreement. 

ARTICLE II 
 DECLARATION
OF TRUST 
 Section 2.01 Declaration of Trust. The Trustee hereby declares the creation of a Trust, designated the
“Spirit Airlines Pass Through Trust 2017-1A” (the “Class A Trust”), for the benefit of the Holders of the Class A Certificates to be issued in respect of such Class A Trust,
and the initial Holders of the Class A Certificates, as grantors of such Class A Trust, by their respective acceptances of the Class A Certificates, join in the creation of such Class A Trust with the Trustee. The Trustee, by the
execution and delivery of this Trust Supplement, acknowledges its acceptance of all right, title and interest in and to the Trust Property to be acquired pursuant to Section 7.01(b) of this Trust Supplement, the NPA and the Participation
Agreements and the Trustee will hold such right, title and interest for the benefit of all present and future Holders of the Class A Certificates, upon the trusts set forth in the Basic Agreement and this Trust Supplement. The provisions of
this Section 2.01 supersede and replace the provisions of Sections 2.03 of the Basic Agreement, with respect to the Class A Trust. 

Section 2.02 Permitted Activities. The Class A Trust may only engage in the transactions contemplated by the Operative
Agreements, subject to Section 9.05 of this Trust Supplement. 
 ARTICLE III 

THE CERTIFICATES 

Section 3.01 The Certificates. There is hereby created a series of Certificates to be issued under this Agreement designated as
“Spirit Airlines Pass Through Certificates, Series 2017-1A” (the “Class A Certificates”). Each Class A Certificate represents a Fractional Undivided Interest in the
Class A Trust created hereby. The Class A Certificates shall be the only instruments evidencing a Fractional Undivided Interest in the Class A Trust. The Class A Certificates do not represent indebtedness of the Class A
Trust, and references herein to interest accruing on the Class A Certificates are included for purposes of computation only. 

Section 3.02 Terms and Conditions. The terms and conditions applicable to the Class A Certificates and the Class A Trust
are as follows: 
 (a) The aggregate face amount of the Class A Certificates that may be authenticated and delivered under this
Agreement (except for Class A Certificates authenticated and delivered upon registration of transfer of, or in exchange for, or in lieu of, other Class A Certificates pursuant to Sections 3.03, 3.04, 3.05 and 3.06 of the Basic
Agreement and Section 4.03 of this Trust Supplement) is $82,366,000. 
 (b) The “Cut-off
Date” is the earlier of (i) the day after the Delivery Period Termination Date, and (ii) the date on which a Triggering Event occurs. 

  

					
		  	8	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 (c) The distribution dates with respect to any payment of Scheduled Payments (each such
distribution date, a “Regular Distribution Date”) shall be February 15 and August 15 of each year, commencing on August 15, 2018, until payment of all of the Scheduled Payments to be made under the Equipment Notes has been
made; provided, however, that, if any such day shall not be a Business Day, the related distribution shall be made on the next succeeding Business Day without additional interest. The principal amount of the Series A Equipment Notes to
be held by the Class A Trust is scheduled for payment on February 15 and August 15 in certain years, commencing on August 15, 2018 and ending on the applicable date specified under the heading “Maturity” on Schedule I
with respect to the related Aircraft, as set out in Schedule III to the NPA. 
 (d) The Special Distribution Date with respect to the
Class A Certificates means any Business Day on which a Special Payment is to be distributed pursuant to this Agreement. 
 (e) At the
Escrow Agent’s request under the Escrow Agreement, the Trustee shall affix the corresponding Escrow Receipt to each Class A Certificate. In any event, any transfer or exchange of any Class A Certificate shall also effect a transfer or
exchange of the related Escrow Receipt. Prior to the Final Withdrawal Date, no transfer or exchange of any Class A Certificate shall be permitted unless the corresponding Escrow Receipt is attached thereto and also is so transferred or
exchanged. By acceptance of any Class A Certificate to which an Escrow Receipt is attached, each holder of such a Class A Certificate acknowledges and accepts the restrictions on transfer of the Escrow Receipt as set forth herein, in such
Escrow Receipt, and in the Escrow Agreement. 
 (f) The Class A Certificates shall be in the form attached hereto as Exhibit A,
shall be Book-Entry Certificates (subject to Section 3.05(d) of the Basic Agreement and Section 4.03 of this Trust Supplement), and shall be subject to the conditions set forth in the Letter of Representations between the Class A
Trust and The Depository Trust Company and any successor agency thereto (“DTC”), as initial Clearing Agency, attached hereto as Exhibit B. 

(g) The proceeds of the offering of Class A Certificates issued by the Class A Trust and related Escrow Receipts shall be deposited
in the Accounts and shall be used in accordance with the Escrow Agreement, the Deposit Agreement and the NPA to acquire from time to time the Series A Equipment Notes described in Schedule I that relate to the Aircraft and to the Note Documents
described in Schedule II. 
 (h) Any Person acquiring or accepting a Class A Certificate or an interest therein will, by such
acquisition or acceptance, be deemed to (i) represent and warrant to the Company, the Loan Trustees and the Trustee that either (1) no assets of a Plan or any trust established with respect to a Plan have been used to purchase or hold
Class A Certificates or an interest therein or (2) the purchase and holding of Class A Certificates or interests therein by such Person are exempt from the prohibited transaction restrictions of ERISA and the Code or provisions of
Similar Law pursuant to one or more prohibited transaction statutory or administrative exemptions or similar exemptions under Similar Law and (ii) direct the Trustee to invest the assets held in the Trust pursuant to, and take all other actions
contemplated by, the terms and conditions of the Basic Agreement, this Trust Supplement, the Intercreditor Agreement, the Deposit Agreement, the Escrow Agreement, the NPA, and each Participation Agreement. 

(i) Any Person who is an ERISA Plan and is acquiring or accepting a Class A Certificate or an interest therein will, by such acquisition
or acceptance, be deemed to represent and warrant to the Company, the Loan Trustees and the Trustee that the decision to acquire or accept the Class A Certificate or interest therein has been made by a duly authorized fiduciary of the ERISA
Plan that (i) is independent (as that term is used in 29 C.F.R. 2510.3-21(c)(1)) of the Company and its Affiliates and there is no financial interest, ownership interest, or other relationship, agreement
or 

  

					
		  	9	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
understanding or otherwise that would limit its ability to carry out its fiduciary responsibility to the ERISA Plan; (ii) is a bank, insurance carrier, registered investment adviser, a
registered broker-dealer, or an independent fiduciary that holds, or has under management or control, total assets of at least $50 million (in each case, as specified in 29 C.F.R.
2510.3-21(c)(1)(i)(A)-(E)); (iii) is capable of evaluating investment risks independently, both in general and with regard to particular transactions and investment strategies (including, without limitation,
with respect to the decision to acquire or accept the Class A Certificate or interest therein); (iv) has been fairly informed that the Company and its Affiliates have not and will not undertake to provide impartial investment advice, or to give
advice in a fiduciary capacity, in connection with the acquisition or acceptance of the Class A Certificate or interest therein; (v) has been fairly informed that the Company and its Affiliates have financial interests in the ERISA
Plan’s acquisition or acceptance of the Class A Certificate or interest therein, which interests may conflict with the interest of the ERISA Plan, as more fully described in the offering materials; (vi) is a fiduciary under ERISA or
the Code, or both, with respect to the decision to acquire or accept the Class A Certificate or interest therein and is responsible for exercising (and has exercised) independent judgment in evaluating whether to invest the assets of the ERISA
Plan in the Class A Certificate or interest therein; and (vii) is not paying the Company or any of its Affiliates, any fee or other compensation directly for the provision of investment advice (as opposed to other services) in connection
with the ERISA Plan’s acquisition or acceptance of the Class A Certificate or interest therein. 
 (j) The Class A
Certificates will be subject to the following Intercreditor Agreement (and to the extent the terms thereof (including the definitions of defined terms) are inconsistent with the terms of this Agreement, such Intercreditor Agreement shall control):
that certain Intercreditor Agreement, dated as of the date hereof, among Wilmington Trust, National Association, as Trustee, as Class AA Trustee and as Class B Trustee, Commonwealth Bank of Australia, New York Branch, as each Liquidity
Provider, and Wilmington Trust, National Association, as Subordination Agent thereunder (as may be amended, supplemented or otherwise modified from time to time in accordance with its terms, the “Intercreditor Agreement”). Under Article VI
hereof, the Holders of the Class A Certificates, the Class B Certificates, Additional Certificates (if issued) or Refinancing Certificates (if issued) shall have the rights upon the occurrence of a Certificate Buy-Out Event set forth therein. The Trustee and, by acceptance of any Class A Certificate, each Certificateholder thereof, agrees to be bound by all of the provisions of the Intercreditor Agreement, including
the subordination provisions of Section 9.09 thereof. 
 (k) The Class A Certificates have the benefit of the Deposit Agreement and
the Escrow Agreement. 
 (l) The Class A Certificates will have the benefit of the following liquidity facility: that certain Revolving
Credit Agreement (2017-1A), dated as of the date hereof, between Wilmington Trust, National Association, as Subordination Agent under the Intercreditor Agreement, as agent and trustee for the Class A
Trust, and the Class A Liquidity Provider. 
 (m) The Responsible Party is the Company. 

(n) The Company, any other obligor upon the Class A Certificates, and any Affiliate of any thereof may acquire, tender for, purchase, own,
hold, become the pledgee of and otherwise deal with any Class A Certificate. 
 (o) The “particular sections of the Note Purchase
Agreement”, for purposes of clause (3) of Section 7.07 of the Basic Agreement, are Section 4.02 of each Participation Agreement. 

  

					
		  	10	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 ARTICLE IV 

ISSUANCE AND TRANSFER OF THE CLASS A CERTIFICATES 

Section 4.01 Issuance of Class A Certificates. (a) The Class A Certificates will be issued in minimum
denominations of $2,000 (or such other denomination that is the lowest integral multiple of $1,000 that is, at the time of issuance, equal to at least 1,000 euros) and integral multiples of $1,000 in excess thereof, except that one Certificate may
be issued in a different denomination. Each Class A Certificate shall be dated the date of its authentication. 
 (b) The Class A
Certificates shall be issued initially in the form of one or more global Certificates in definitive, fully registered form without interest coupons, substantially in the form of Exhibit A hereto (each, a “Global Certificate”), duly
executed and authenticated by the Trustee as hereinafter provided. Each Global Certificate will be registered in the name of a nominee for DTC for credit to the account of members of, or participants in, DTC (“DTC Participants”) or to the
account of indirect participants that clear through or maintain a custodial relationship with a DTC Participant, either directly or indirectly (“Indirect Participants”), and will be deposited with the Trustee, as custodian for DTC. The
aggregate face amount of a Global Certificate may from time to time be decreased by adjustments made on the records of DTC or its nominee, or of the Trustee, as custodian for DTC or its nominee, as hereinafter provided, which adjustments shall be
conclusive as to the aggregate face amount of any such Global Certificate. 
 (c) [Reserved] 

(d) [Reserved] 
 (e) Certificated
Certificates in registered form shall be issued in substantially the form set forth as Exhibit A hereto (the “Definitive Certificates”) and shall be in fully registered form and shall be typed, printed, lithographed or engraved or produced
by any combination of these methods or may be produced in any other manner, all as determined by the officers executing such Definitive Certificates, as evidenced by their execution of such Definitive Certificates. 

Section 4.02 Legends. (a) Each Global Certificate shall bear the following legend on the face thereof: 

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”),
TO THE TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IN EXCHANGE FOR THIS CERTIFICATE IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC (AND ANY PAYMENT HEREON IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS
WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN. 
 (b) Each Class A Certificate shall
bear the following legend on the face thereof: 
 BY ITS ACQUISITION HEREOF, THE HOLDER REPRESENTS THAT EITHER (A) NO ASSETS OF A PLAN
OR ANY TRUST ESTABLISHED WITH RESPECT TO A PLAN HAVE BEEN USED TO PURCHASE OR HOLD THIS CERTIFICATE OR 

  

					
		  	11	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
AN INTEREST HEREIN OR (B) THE PURCHASE AND HOLDING OF THIS CERTIFICATE OR INTEREST HEREIN BY SUCH A PERSON ARE EXEMPT FROM THE PROHIBITED TRANSACTION RESTRICTIONS OF ERISA AND THE CODE OR
PROVISIONS OF SIMILAR LAW PURSUANT TO ONE OR MORE PROHIBITED TRANSACTION STATUTORY OR ADMINISTRATIVE EXEMPTIONS OR SIMILAR EXEMPTIONS UNDER SIMILAR LAW. 

FURTHER, BY ITS ACQUISITION HEREOF, A HOLDER WHO IS AN ERISA PLAN REPRESENTS THAT THE DECISION TO ACQUIRE OR ACCEPT THIS CERTIFICATE OR
INTEREST HEREIN HAS BEEN MADE BY A DULY AUTHORITZED FIDUCIARY OF THE ERISA PLAN THAT (A) IS INDEPENDENT (AS THAT TERM IS USED IN 29 C.F.R. 2510-3-21(c)(1)) OF THE
COMPANY AND ITS AFFILIATES AND THERE IS NO FINANCIAL INTEREST, OWNERSHIP INTEREST, OR OTHER RELATIONSHIP, AGREEMENT OR UNDERSTANDING OR OTHERWISE THAT WOULD LIMIT ITS ABILITY TO CARRY OUT ITS FIDUCIARY RESPONSIBILITY TO THE ERISA PLAN; (B) IS A
BANK, INSURANCE CARRIER, REGISTERED INVESTMENT ADVISER, A REGISTERED BROKER-DEALER, OR AN INDEPENDENT FIDUCIARY THAT HOLDS, OR HAS UNDER MANAGEMENT OR CONTROL, TOTAL ASSETS OF AT LEAST $50 MILLION (IN EACH CASE, AS SPECIFIED IN 29 C.F.R. 2510.3-21(c)(1)(i)(A)-(E)); (C) IS CAPABLE OF EVALUATING INVESTMENT RISKS INDEPENDENTLY, BOTH IN GENERAL AND WITH REGARD TO PARTICULAR TRANSACTIONS AND INVESTMENT STRATEGIES (INCLUDING, WITHOUT LIMITATION, WITH
RESPECT TO THE DECISION TO ACQUIRE OR ACCEPT THIS CERTIFICATE OR INTEREST HEREIN); (D) HAS BEEN FAIRLY INFORMED THAT THE COMPANY AND ITS AFFILIATES HAVE NOT AND WILL NOT UNDERTAKE TO PROVIDE IMPARTIAL INVESTMENT ADVICE, OR TO GIVE ADVICE IN A
FIDUCIARY CAPACITY, IN CONNECTION WITH THE ACQUISITION OR ACCEPTANCE OF THIS CERTIFICATE OR INTEREST HEREIN; (E) HAS BEEN FAIRLY INFORMED THAT THE COMPANY AND ITS AFFILIATES HAVE FINANCIAL INTERESTS IN THE ERISA PLAN’S ACQUISITION OR
ACCEPTANCE OF THIS CERTIFICATE OR INTEREST HEREIN, WHICH INTERESTS MAY CONFLICT WITH THE INTEREST OF THE ERISA PLAN, AS MORE FULLY DESCRIBED IN THE OFFERING MATERIALS; (F) IS A FIDUCIARY UNDER ERISA OR THE CODE, OR BOTH, WITH RESPECT TO THE
DECISION TO ACQUIRE OR ACCEPT THIS CERTIFICATE OR INTEREST HEREIN AND IS RESPONSIBLE FOR EXERCISING (AND HAS EXERCISED) INDEPENDENT JUDGMENT IN EVALUATING WHETHER TO INVEST THE ASSETS OF THE ERISA PLAN IN THIS CERTIFICATE OR INTEREST HEREIN; AND
(G) IS NOT PAYING FOR THE COMPANY OR ANY OF ITS AFFILIATES, ANY FEE OR OTHER COMPENSATION DIRECTLY FOR THE PROVISION OF INVESTMENT ADVICE (AS OPPOSED TO OTHER SERVICES) IN CONNECTION WITH THE ERISA PLAN’S ACQUISITION OR ACCEPTANCE OF THIS
CERTIFICATE OR INTEREST HEREIN. 
 CERTAIN TERMS USED IN THE FOREGOING PARAGRAPHS SHALL HAVE THE MEANINGS SPECIFIED IN THE AGREEMENT. 

Section 4.03 Book-Entry Provisions for Global Certificates. (a) DTC Participants shall have no rights under this Agreement
with respect to any Global Certificate held on their behalf by DTC, or the Trustee as its custodian, and DTC may be treated by the Trustee and any agent of the Trustee as the absolute owner of such Global Certificate for all purposes whatsoever.
Notwithstanding the 

  

					
		  	12	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)










	
	foregoing, nothing herein shall prevent the Trustee or any agent of the Trustee from giving effect to any written certification, proxy or other authorization furnished by DTC or shall impair, as between DTC and its DTC
Participants, the operation of customary practices governing the exercise of the rights of a holder of any Class A Certificate. Upon the issuance of any Global Certificate, the Registrar or its duly appointed agent shall record Cede &
Co. or another nominee of DTC as the registered holder of such Global Certificate.

 (b) Transfers of any Global Certificate shall be limited to transfers of such Global Certificate in whole, but
not in part, to nominees of DTC, its successor or such successor’s nominees. Beneficial interests in Global Certificates may be transferred in accordance with the rules and procedures of DTC and the provisions of Section 4.02 of this Trust
Supplement. Beneficial interests in Global Certificates shall be delivered to all beneficial owners thereof in the form of Definitive Certificates, if (i) DTC notifies the Trustee in writing that it is no longer willing or able to discharge
properly its responsibilities as depositary for the Global Certificates, and a successor depositary is not appointed by the Trustee within 90 days of such notice, (ii) the Company, at its option, advises the Trustee in writing that it
elects to terminate the book-entry system through DTC or (iii) after the occurrence and during the continuance of an Event of Default, Class A Certificateholders with Fractional Undivided Interests aggregating not less than a majority in
interest in the Class A Trust advise the Trustee, the Company and DTC through DTC Participants in writing that the continuation of a book-entry system through DTC (or a successor thereto) is no longer in the Class A
Certificateholders’ best interests. Neither the Company nor the Trustee shall be liable if the Company or the Trustee is unable to locate a qualified successor clearing system. 

(c) [Reserved] 
 (d) In connection
with the transfer of the entire amount of a Global Certificate to the beneficial owners thereof pursuant to paragraph (b) of this Section 4.03, such Global Certificate shall be deemed to be surrendered to the Trustee for cancellation, and
the Trustee shall execute, authenticate and deliver to each beneficial owner, in exchange for the beneficial interest thereof in such Global Certificate, an equal aggregate face amount of Definitive Certificates of authorized denominations, in each
case as such beneficial owner and related aggregate face amount shall have been identified and otherwise set forth (together with such other information as may be required for the registration of such Definitive Certificates) in registration
instructions that shall have been delivered by or on behalf of DTC to the Trustee. None of the Company, the Registrar, the Paying Agent nor the Trustee shall be liable for any delay in delivery of such registration instructions and each such Person
may conclusively rely on, and shall be protected in relying on, such registration instructions. Upon the issuance of any Definitive Certificate, the Trustee shall recognize the Person in whose name such Definitive Certificate is registered in the
Register as a Certificateholder hereunder. 
 (e) The registered Holder of a Global Certificate may grant proxies and otherwise authorize any
Person, including DTC Participants and Persons that may hold interests through DTC Participants, to take any action which a Holder is entitled to take under this Agreement or the Class A Certificates. 

(f) Neither the Company, nor the Trustee, nor the Registrar, nor the Paying Agent shall have any responsibility or liability for: (i) any
aspect of the records relating to or payments made on account of beneficial ownership interests in the Global Certificates, (ii) maintaining, supervising or reviewing any records relating to such beneficial ownership interests or (iii) the
performance by DTC, any DTC Participant or any Indirect Participant of their respective obligations under the rules, regulations and procedures creating and affecting DTC and its operation or any other statutory, regulatory, contractual or customary
procedures governing their obligations. 

  

					
		  	13	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 ARTICLE V 

DISTRIBUTION; STATEMENTS TO CERTIFICATEHOLDERS 

Section 5.01 Statements to Certificateholders. (a) On each Regular Distribution Date and Special Distribution Date, the
Trustee will include with each distribution to the Class A Certificateholders a statement, giving effect to the distribution to be made on such Regular Distribution Date or Special Distribution Date, setting forth the following information (per
$1,000 aggregate face amount of Class A Certificates as to clauses (ii), (iii), (iv) and (v) below): 
 (i)
the aggregate amount of funds distributed on such Distribution Date under this Agreement and the Escrow Agreement, indicating the amount, if any, allocable to each source (including any portion thereof paid by the Class A Liquidity Provider);

 (ii) the amount of such distribution under this Agreement allocable to principal and the amount allocable to Premium (if
any); 
 (iii) the amount of such distribution under this Agreement allocable to interest (including any portion thereof paid
by the Class A Liquidity Provider); 
 (iv) the amount of such distribution under the Escrow Agreement allocable to
interest, if any; 
 (v) the amount of such distribution under the Escrow Agreement allocable to unused Deposits, if any; and

 (vi) the Pool Balance and the Pool Factor. 

With respect to the Class A Certificates registered in the name of DTC or its nominee, on the Record Date prior to each Regular
Distribution Date and Special Distribution Date, the Trustee will request that DTC post on its Internet bulletin board a securities position listing setting forth the names of all the DTC Participants reflected on DTC’s books as holding
interests in the Class A Certificates on such Record Date. On each Regular Distribution Date and Special Distribution Date, the Trustee will mail to each such DTC Participant whose name has been provided by DTC the statement described above and
will make available additional copies as requested by such DTC Participants for forwarding to holders of interests in the Class A Certificates. 

(b) Within a reasonable period of time after the end of each calendar year but not later than the latest date permitted by law, the Trustee
shall furnish to each Person who at any time during such calendar year was a Class A Certificateholder of record a statement containing the sum of the amounts determined pursuant to clauses (a)(i), (a)(ii), (a)(iii), (a)(iv) and (a)(v)
above for such calendar year or, in the event such Person was a Class A Certificateholder of record during a portion of such calendar year, for the applicable portion of such year, and such other items as are readily available to the Trustee
and which a Class A Certificateholder may reasonably request as necessary for the purpose of such Certificateholder’s preparation of its United States federal income tax returns or foreign income tax returns. With respect to Class A
Certificates registered in the name of DTC or its nominee, such statement and such other items shall be prepared on the basis of information supplied to the Trustee by the DTC Participants and shall be delivered by the Trustee to such DTC
Participants to be available for forwarding by such DTC Participants to the holders of beneficial interests in the Class A Certificates. 

(c) Promptly following: 

(i) the Delivery Period Termination Date, or, if later, the date of any Final Withdrawal (the later of such dates, the
“Escrow Period Termination Date”), if there has been, on 

  

					
		  	14	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
or prior to the Escrow Period Termination Date, (A) any change in the information set forth in clauses (y) and (z) below from that set forth on page
S-54 of the Prospectus Supplement, or (B) any early redemption or purchase of, or any default in the payment of principal or interest in respect of, any of the Series A Equipment Notes held in the
Class A Trust, any Event of Loss Withdrawal or any Final Withdrawal, and 
 (ii) the date of any early redemption or
purchase of, or any default in the payment of principal or interest in respect of, any of the Series A Equipment Notes held in the Class A Trust, in either case described in this clause (ii), occurring after the Escrow Period Termination
Date, 
 the Trustee shall furnish to Class A Certificateholders of record on such date a statement setting forth (x) the expected
Pool Balances for each subsequent Regular Distribution Date following the Delivery Period Termination Date or the date of such early redemption, purchase or default, (y) the related Pool Factors for such Regular Distribution Dates, and
(z) the expected principal distribution schedule of the Series A Equipment Notes, in the aggregate, held as Trust Property at the date of such notice. With respect to the Class A Certificates registered in the name of DTC, on the Delivery
Period Termination Date or the date of such early redemption, purchase or default, the Trustee will request from DTC a securities position listing setting forth the names of all DTC Participants reflected on DTC’s books as holding interests in
the Class A Certificates on such date. The Trustee will mail (or in the case of Global Certificates, send electronically in accordance with DTC’s applicable procedures) to each such DTC Participant the statement described above and will
make available additional copies as requested by such DTC Participant for forwarding to holders of interests in the Class A Certificates. 

(d) If the aggregate principal payments scheduled for a Regular Distribution Date prior to the Delivery Period Termination Date differ from the
amount thereof set forth for the Class A Certificates on page S-54 of the Prospectus Supplement, by no later than the 15th day prior to such Regular Distribution Date, the Trustee shall mail (or in the
case of Global Certificates, send electronically in accordance with DTC’s applicable procedures) written notice of the actual amount of such scheduled payments to the Class A Certificateholders of record as of a date within 15 Business
Days prior to the date of mailing or sending, as applicable. 
 (e) The provisions of this Section 5.01 supersede and replace the
provisions of Section 4.03 of the Basic Agreement in their entirety with respect to the Class A Trust. 
 ARTICLE VI 

DEFAULT 

Section 6.01 Purchase Rights of Certificateholders. (a) By acceptance of its Class A Certificate, each Class A
Certificateholder agrees that at any time after the occurrence and during the continuation of a Certificate Buy-Out Event: 

(i) so long as no Class B Certificateholder or Additional Certificateholder has elected to exercise its rights to purchase
the Class AA Certificates and the Class A Certificates pursuant to, and given notice of such election in accordance with, this Section 6.01(a) (upon such election and notification thereof, the right specified in this
Section 6.01(a)(i) shall be suspended and (x) upon consummation of the purchase pursuant to such election, be terminated with respect to such Certificate Buy-Out Event, or (y) upon failure to
consummate such purchase on the proposed purchase date, such right shall be revived), each Class A Certificateholder (other than the Company or any of its Affiliates) shall have the right to purchase, at the purchase price set forth in the
Class AA Trust Agreement, all, but not less than all, of the Class AA Certificates upon ten days’ prior written irrevocable notice to the Trustee, the Class AA Trustee and each other Class A Certificateholder, on the third
Business Day following the expiration of such ten-

  

					
		  	15	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
day notice period, provided that (A) if prior to the end of such ten-day period any other Class A Certificateholder(s) (other than the
Company or any of its Affiliates) notifies such purchasing Class A Certificateholder that such other Class A Certificateholder(s) want(s) to participate in such purchase, then such other Class A Certificateholder(s) (other than the
Company or any of its Affiliates) may join with the purchasing Class A Certificateholder to purchase all, but not less than all, of the Class AA Certificates pro rata based on the Fractional Undivided Interest in the Class A Trust
held by each such Class A Certificateholder and (B) upon consummation of such purchase no Class A Certificateholder shall have a right to purchase the Class AA Certificates pursuant to this Section 6.01(a)(i) during the
continuance of such Certificate Buy-Out Event, 
 (ii) so long as no Additional
Certificateholder has elected to exercise its rights to purchase Certificates pursuant to, and given notice of such election in accordance with, this Section 6.01(a) (upon such election and notification thereof, the right specified in this
Section 6.01(a)(ii) shall be suspended and (x) upon consummation of the purchase pursuant to such election, be terminated with respect to such Certificate Buy-Out Event, or (y) upon failure to
consummate such purchase on the proposed purchase date, such right shall be revived), each Class B Certificateholder (other than the Company or any of its Affiliates) shall have the right to purchase, at the purchase price set forth in the
Class AA Trust Agreement and herein, respectively, all, but not less than all, of the Class AA Certificates and the Class A Certificates upon ten days’ prior written irrevocable notice to the Trustee, the Class AA Trustee,
the Class B Trustee and each other Class B Certificateholder, on the third Business Day following the expiration of such ten-day notice period, provided that (A) if prior to the end of
such ten-day period any other Class B Certificateholder(s) (other than the Company or any of its Affiliates) notifies such purchasing Class B Certificateholder that such other Class B
Certificateholder(s) want(s) to participate in such purchase, then such other Class B Certificateholder(s) (other than the Company or any of its Affiliates) may join with the purchasing Class B Certificateholder to purchase all, but not
less than all, of the Class AA Certificates and the Class A Certificates pro rata based on the Fractional Undivided Interest in the Class B Trust held by each such Class B Certificateholder and (B) upon consummation of such
purchase no Class B Certificateholder shall have a right to purchase the Class AA Certificates and the Class A Certificates pursuant to this Section 6.01(a)(ii) during the continuance of such Certificate Buy-Out Event, 
 (iii) if any Additional Certificates are issued by an Additional Trust,
so long as no Junior Additional Certificateholder (if any) has elected to exercise its rights to purchase Certificates pursuant to, and given notice of such election in accordance with, this Section 6.01(a) (upon such election and notification
thereof, the right specified in this Section 6.01(a)(iii) shall be suspended and (x) upon consummation of the purchase pursuant to such election, be terminated with respect to such Certificate
Buy-Out Event, or (y) upon failure to consummate such purchase on the proposed purchase date, such right shall be revived), each Additional Certificateholder (other than the Company or any of its
Affiliates) shall have the right (which shall not expire upon any purchase of the Class AA Certificates or the Class AA Certificates and Class A Certificates pursuant to clause (i) or (ii) above, respectively) to purchase
all, but not less than all, of the Class AA Certificates, the Class A Certificates, the Class B Certificates and any Additional Certificates ranked senior, in priority of payment of “Expected Distributions” therefor under
the Intercreditor Agreement, to the Additional Certificates held by the purchasing Additional Certificateholder upon ten days’ prior written irrevocable notice to the Trustee, the Class AA Trustee, the Class B Trustee, the trustee of
any Additional Trust with respect to any Additional Certificates that rank senior, in priority of payment of “Expected Distributions” therefor under the Intercreditor Agreement, to the Additional Certificates held by the purchasing
Additional Certificateholder and each other Additional Certificateholder of the same class, on the third Business Day following the expiration of such ten-day notice period, provided that (A) if
prior to the end of such ten-day 

  

					
		  	16	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
period any other Additional Certificateholder(s) of such class (other than the Company or any of its Affiliates) notifies such purchasing Additional Certificateholder that such other Additional
Certificateholder(s) want(s) to participate in such purchase, then such other Additional Certificateholder(s) (other than the Company or any of its Affiliates) may join with the purchasing Additional Certificateholder to purchase all, but not less
than all, of the Class AA Certificates, the Class A Certificates, the Class B Certificates and such senior Additional Certificates pro rata based on the Fractional Undivided Interest in the applicable Additional Trust held by each
such Additional Certificateholder and (B) upon consummation of such purchase no Additional Certificateholder of such class shall have a right to purchase the Class AA Certificates, the Class A Certificates, the Class B
Certificates and such senior Additional Certificates pursuant to this Section 6.01(a)(iii) during the continuance of such Certificate Buy-Out Event, and 

(iv) if any Refinancing Certificates are issued, each Refinancing Certificateholder shall have the same right (subject to the
same terms and conditions) to purchase Certificates pursuant to this Section 6.01(a) (and to receive notice in connection therewith) as the Holders of the Class that such Refinancing Certificates refinanced. 

The purchase price with respect to the Class A Certificates shall be equal to the Pool Balance of the Class A Certificates, together
with accrued and unpaid interest in respect thereof to the date of such purchase, and any other amounts then due and payable to the Class A Certificateholders under this Agreement, the Intercreditor Agreement, the Escrow Agreement, any Series A
Equipment Note held as the property of the Class A Trust or the related Indenture and Participation Agreement or on or in respect of the Class A Certificates but without any Premium, provided, however, that if such purchase
occurs after (x) a record date specified in Section 2.03 of the Escrow Agreement relating to the distribution of unused Deposits and/or accrued and unpaid interest on Deposits and prior to or on the related distribution date under the
Escrow Agreement, such purchase price shall be reduced by the aggregate amount of unused Deposits and/or interest to be distributed under the Escrow Agreement (which deducted amounts shall remain distributable to, and may be retained by, the
Class A Certificateholders as of such record date) or (y) the Record Date relating to any Distribution Date, such purchase price shall be reduced by the amount to be distributed hereunder on such related Distribution Date (which deducted
amounts shall remain distributable to, and may be retained by, the Class A Certificateholders as of such Record Date); provided further that no such purchase of Class A Certificates pursuant to this Section 6.01(a) shall
be effective unless the purchaser(s) shall certify to the Trustee that contemporaneously with such purchase, such purchaser(s) is purchasing, pursuant to the terms of this Agreement, the Class AA Trust Agreement, the Class B Trust
Agreement, the applicable Additional Trust Agreement (if any) or the applicable Refinancing Trust Agreement (as the case may be), and the Intercreditor Agreement, all of the Class AA Certificates, the Class A Certificates, the Class B
Certificates and, if applicable, the Additional Certificates that rank senior, in priority of payment of “Expected Distributions” therefor under the Intercreditor Agreement, to the Additional Certificates held by the purchasing Additional
Certificateholder(s) and, if applicable, the Refinancing Certificates that are senior to the securities held by such purchaser(s). Each payment of the purchase price of the Class A Certificates referred to in the first sentence of this
paragraph shall be made to an account or accounts designated by the Trustee and each such purchase shall be subject to the terms of this Section 6.01(a). Each Class A Certificateholder agrees by its acceptance of its Class A
Certificate that it will, upon payment from such Class B Certificateholder(s), Additional Certificateholder(s) or Refinancing Certificateholder(s), as the case may be, of the purchase price set forth in the first sentence of this paragraph,
forthwith sell, assign, transfer and convey to the purchaser(s) thereof (without recourse, representation or warranty of any kind except as to its own acts) all of the right, title, interest and obligation of such Class A Certificateholder in
this Agreement, the Escrow Agreement, the Deposit Agreement, the Intercreditor Agreement, the Class A Liquidity Facility, the NPA, the Note Documents 

  

					
		  	17	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
and all Class A Certificates and Escrow Receipts held by such Class A Certificateholder (excluding all right, title and interest under any of the foregoing to the extent such right,
title or interest is with respect to an obligation not then due and payable as respects any action or inaction or state of affairs occurring prior to such sale) and the purchaser(s) shall assume all of such Class A Certificateholder’s
obligations under this Agreement, the Escrow Agreement, the Deposit Agreement, the Intercreditor Agreement, the Class A Liquidity Facility, the NPA, the Note Documents and all such Class A Certificates and Escrow Receipts. The Class A
Certificates will be deemed to be purchased on the date payment of the purchase price is made notwithstanding the failure of any Class A Certificateholder to deliver any Class A Certificate and, upon such a purchase, (i) the
Class A Certificateholders shall have no further rights with respect to the Class A Certificates and (ii) if the purchaser(s) shall so request, each such Class A Certificateholder will comply with all the provisions of
Section 3.04 of the Basic Agreement and the applicable provisions of this Trust Supplement to enable new Class A Certificates to be issued to the purchaser(s) in such denominations otherwise authorized under this Agreement as it shall
request. All charges and expenses in connection with the issuance of any such new Class A Certificates shall be borne by the purchaser(s) thereof. 

(b) This Section 6.01 supplements and, to the extent inconsistent with any provision of Section 6.01(b) of the Basic Agreement,
replaces the provisions of Section 6.01(b) of the Basic Agreement. Notwithstanding anything to the contrary set forth herein or in any Operative Agreement, the provisions of this Section 6.01 may not be amended in any manner without the
consent of each Class AA Certificateholder, each Class A Certificateholder, each Class B Certificateholder and each Additional Certificateholder (if any) or, as the case may be, Refinancing Certificateholder (if any) (in each case,
other than the Company or any of its Affiliates in its respective capacity as a Certificateholder) that would be adversely affected thereby; provided that the purchase price under this Section 6.01 (as in effect on the date hereof) for
any Certificate held by the Company or any of its Affiliates shall not be modified without the prior written consent of the Company. For the avoidance of doubt, if a Certificate Buy-Out Event ceases to exist
and another Certificate Buy-Out Event occurs and is continuing, the purchase rights set forth in Section 6.01(a) shall be revived notwithstanding any exercise of such rights during the continuance of any
preceding Certificate Buy-Out Event. 
 ARTICLE VII 

THE TRUSTEE 

Section 7.01 Delivery of Documents; Delivery Dates. (a) The Trustee is hereby directed (i) to execute and deliver the
Intercreditor Agreement, the Escrow Agreement and the NPA on or prior to the date of the initial issuance of the Class A Certificates (the “Issuance Date”), each in the form delivered to the Trustee by the Company, and
(ii) subject to the respective terms thereof, to perform its obligations thereunder. Upon request of the Company and the satisfaction or waiver of the closing conditions specified in the Underwriting Agreement, the Trustee shall execute,
deliver, authenticate, issue and sell Class A Certificates in authorized denominations equaling in the aggregate the amount set forth, with respect to the Class A Trust, in Schedule I to the Underwriting Agreement evidencing the entire
ownership interest in the Class A Trust, which amount equals the maximum aggregate principal amount of Series A Equipment Notes which may be purchased from time to time by the Trustee pursuant to the NPA. Except as provided in
Sections 3.03, 3.04, 3.05 and 3.06 of the Basic Agreement or Section 4.03 of this Trust Supplement, the Trustee shall not execute, authenticate or deliver Class A Certificates in excess of the aggregate amount specified in this
paragraph. The provisions of this Section 7.01(a) supersede and replace the first three sentences of Section 2.02(a) of the Basic Agreement and the first sentence of Section 3.02(a) of the Basic Agreement, with respect to the
Class A Trust. 
 (b) On or after the Issuance Date, the Company may deliver from time to time, and in accordance with Section 1(b)
of the NPA, to the Trustee a Funding Notice relating to one or more 

  

					
		  	18	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
Series A Equipment Notes. After receipt of such a Funding Notice and in any case no later than one Business Day prior to a Funding Date as to which such Funding Notice relates (the
“Applicable Funding Date”), the Trustee shall (as and when specified in the Funding Notice) deliver to the Escrow Agent the Withdrawal Certificates and related Applicable Notices of Purchase Withdrawal, as contemplated by
Section 1.02(c) of the Escrow Agreement and by such Funding Notice. The Trustee shall (as and when specified in such Funding Notice), subject to the conditions set forth in Section 2 of the NPA, enter into and perform its obligations under
the Participation Agreement specified in such Funding Notice (the “Applicable Participation Agreement”) and cause such certificates, documents and legal opinions relating to the Trustee to be duly delivered as required by the Applicable
Participation Agreement. If at any time prior to the Applicable Funding Date, the Trustee receives from the Company a notice pursuant to the first sentence of Section 1(f) of the NPA, then the Trustee shall give notice to the Depositary (with a
copy to the Escrow Agent) of the cancellation of such Notice of Purchase Withdrawal relating to such Deposit or Deposits on such Applicable Funding Date as contemplated by Section 2.3 of the Deposit Agreement. Upon satisfaction of the
conditions specified in the NPA and the Applicable Participation Agreement, the Trustee shall purchase the applicable Series A Equipment Notes with the proceeds of the withdrawals of one or more Deposits made on the Applicable Funding Date in
accordance with the terms of the Deposit Agreement and the Escrow Agreement. The purchase price of such Series A Equipment Notes shall equal the principal amount of such Series A Equipment Notes. Amounts withdrawn from such Deposit or Deposits in
excess of the purchase price of the Series A Equipment Notes or to the extent not applied on the Applicable Funding Date to the purchase price of the Series A Equipment Notes shall be re-deposited by the
Trustee with the Depositary on the Applicable Funding Date in accordance with the terms of the Deposit Agreement. The provisions of this Section 7.01(b) supersede and replace the last sentence of Section 2.02(a) of the Basic Agreement and
the provisions of Section 2.02(b) of the Basic Agreement with respect to the Class A Trust, and no provisions of the Basic Agreement relating to Postponed Notes and Section 2.02(b) of the Basic Agreement shall apply to the
Class A Trust. 
 (c) With respect to the Class A Trust, Section 4.01(b) of the Basic Agreement is superseded and replaced in
its entirety with the following: “The Trustee shall establish and maintain on behalf of the Class A Certificateholders a Special Payments Account as one or more accounts, which shall be non-interest
bearing except as provided in Section 4.04 of the Basic Agreement. The Trustee shall hold the Special Payments Account in trust for the benefit of the Class A Certificateholders and shall make or permit withdrawals therefrom only as
provided in the Agreement or the Intercreditor Agreement. On each day when one or more Special Payments are made to the Trustee under the Intercreditor Agreement, the Trustee, upon receipt thereof, shall immediately deposit the aggregate amount of
such Special Payments in the Special Payments Account.” 
 (d) With respect to the Class A Trust, the second through fifth
sentences of Section 4.02(c) of the Basic Agreement shall be superseded and replaced in their entirety with the following sentence: “Subject to the provisions of the Intercreditor Agreement: (i) in the event of redemption or purchase
of Series A Equipment Notes held in the Class A Trust, such notice shall be mailed (or in the case of Global Certificates, sent electronically in accordance with DTC’s applicable procedures) not less than 15 days prior to the Special
Distribution Date for the Special Payment resulting from such redemption or purchase, which Special Distribution Date shall be the date of such redemption or purchase; and (ii) in the case of any other Special Payments, such notice of Special
Payment shall be mailed (or in the case of Global Certificates, sent electronically in accordance with DTC’s applicable procedures) as soon as practicable after the Trustee has confirmed that it has received funds for such Special Payment and
shall state the Special Distribution Date for such Special Payment, which shall occur 15 days after the date of such notice of Special Payment or (if such 15th day is not practicable) as soon as practicable thereafter.” 

  

					
		  	19	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 (e) With respect to the Class A Trust, clause (ii) of the sixth sentence of
Section 4.02(c) of the Basic Agreement shall be amended by deleting in its entirety the parenthetical phrase “(taking into account any payment to be made by the Company pursuant to Section 2.02(b)).” 

Section 7.02 Withdrawal of Deposits. If any Deposits remain outstanding on the Business Day next succeeding the Cut-off Date, the Trustee shall promptly give the Escrow Agent notice, as contemplated by clause (ii) of Section 1.02(f) of the Escrow Agreement, that the Trustee’s obligation to purchase Series A
Equipment Notes under the NPA has terminated and the Cut-off Date has occurred. 
 Section 7.03
The Trustee. (a) Subject to Section 7.04 of this Trust Supplement and Section 7.15 of the Basic Agreement, the Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this
Trust Supplement, the Intercreditor Agreement, the Deposit Agreement, the NPA or the Escrow Agreement or the due execution hereof or thereof by the Company or the other parties thereto (other than the Trustee), or for or in respect of the recitals
and statements contained herein or therein, all of which recitals and statements are made solely by the Company or the other parties thereto (other than the Trustee), except that the Trustee hereby represents and warrants that each of this Trust
Supplement, the Basic Agreement, each Class A Certificate, the Intercreditor Agreement, the NPA and the Escrow Agreement has been executed and delivered by one of its officers who is duly authorized to execute and deliver such document on its
behalf. 
 (b) In addition to the requirements in Section 7.08 of the Basic Agreement, the Trustee shall at all times be a bank or trust
company, organized and doing business under the laws of the United States or any state thereof, a substantial part of the business of which consists of (i) receiving deposits and making loans or (ii) exercising fiduciary powers similar to
those permitted to national banks by the Comptroller of the Currency, and which is subject to supervision and examination by state or federal authority having supervision over banking institutions. 

Section 7.04 Representations and Warranties of the Trustee. The Trustee hereby represents and warrants that: 

(a) the Trustee has full power, authority and legal right to execute, deliver and perform this Trust Supplement, the Intercreditor Agreement,
the Escrow Agreement, the NPA, the Class A Certificates and the Note Documents to which it is or is to become a party and has taken all necessary action to authorize the execution, delivery and performance by it of this Trust Supplement, the
Intercreditor Agreement, the Escrow Agreement, the NPA, the Class A Certificates and the Note Documents to which it is or is to become a party; 

(b) the execution, delivery and performance by the Trustee of this Trust Supplement, the Intercreditor Agreement, the Escrow Agreement, the
NPA, the Class A Certificates and the Note Documents to which it is or is to become a party (i) will not violate any provision of any United States federal law governing its banking powers or the law of the state of the United States where
it is located governing the banking and trust powers of the Trustee or any order, writ, judgment, or decree of any court, arbitrator or governmental authority applicable to the Trustee or any of its assets, (ii) will not violate any provision
of the articles of association or by-laws of the Trustee, and (iii) will not violate any provision of, or constitute, with or without notice or lapse of time, a default under, or result in the creation or
imposition of any lien on any properties included in the Trust Property pursuant to the provisions of, any mortgage, indenture, contract, agreement or other undertaking to which it is a party, which violation, default or lien could reasonably be
expected to have an adverse effect on the Trustee’s performance or ability to perform its duties hereunder or thereunder or on the transactions contemplated herein or therein; 

(c) the execution, delivery and performance by the Trustee of this Trust Supplement, the Intercreditor Agreement, the Escrow Agreement, the
NPA, the Class A Certificates and the Note Documents to which it is or is to become a party will not require the authorization, consent, or approval 

  

					
		  	20	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
of, the giving of notice to, the filing or registration with, or the taking of any other action in respect of, any governmental authority or agency of the United States or the state of the United
States where it is located regulating the banking and corporate trust activities of the Trustee; and 
 (d) this Trust Supplement, the
Intercreditor Agreement, the Escrow Agreement, the NPA, the Class A Certificates and the Note Documents to which it is or is to become a party have been, or will be, as applicable, duly executed and delivered by the Trustee and constitute, or
will constitute, as applicable, the legal, valid and binding agreements of the Trustee, enforceable against it in accordance with their respective terms; provided, however, that enforceability may be limited by (i) applicable
bankruptcy, insolvency, reorganization, moratorium or similar laws affecting the rights of creditors generally and (ii) general principles of equity. 

Section 7.05 Trustee Liens. The Trustee in its individual capacity agrees, in addition to the agreements contained in
Section 7.17 of the Basic Agreement, that it will at its own cost and expense promptly take any action as may be necessary to duly discharge and satisfy in full any Trustee’s Liens on or with respect to the Trust Property which are
attributable to the Trustee in its individual capacity and which are unrelated to the transactions contemplated by the Intercreditor Agreement or the NPA. 

ARTICLE VIII 

ADDITIONAL AMENDMENT; SUPPLEMENTAL AGREEMENTS 

Section 8.01 Amendment of Sections 5.02, 6.07, 7.09, 8.04, 9.01, 12.01 and 12.02 of the Basic Agreement. For purposes of this
Agreement, the Basic Agreement shall be deemed amended as follows: 
 (a) Section 5.02 of the Basic Agreement shall be deemed amended
and restated in its entirety to read as set forth in Part A of Exhibit C. 
 (b) Section 6.07 of the Basic Agreement shall be deemed
amended and restated in its entirety to read as set forth in Part B of Exhibit C. 
 (c) Section 7.09 of the Basic Agreement shall be
deemed amended by amending and restating the second sentence of subsection (e) thereof in its entirety to read as set forth in Part C of Exhibit C. 

(d) Section 8.04 of the Basic Agreement shall be deemed amended by amending and restating subsection (a) thereof in its entirety to
read as set forth in Part D of Exhibit C. 
 (e) Section 9.01 of the Basic Agreement shall be deemed amended by amending and restating
clause (4) thereof in its entirety to read as set forth in Part E of Exhibit C. 
 (f) Section 12.01 of the Basic Agreement shall
be deemed amended and restated in its entirety to read as set forth in Part F of Exhibit C. 
 (g) Section 12.02 of the Basic Agreement
shall be deemed amended and restated in its entirety to read as set forth in Part G of Exhibit C. 
 Section 8.02 Supplemental
Agreements Without Consent of Class A Certificateholders. Without limitation of Section 9.01 of the Basic Agreement (for the avoidance of doubt, as amended by Section 8.01 above), under the terms of, and subject to
the limitations contained in, such Section 9.01 of the Basic Agreement, the Company may (but will not be required to), and the Trustee (subject to Section 9.03 of the Basic Agreement) shall, at the Company’s request, at any time and


  

					
		  	21	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
from time to time, enter into (or, in the case of the Deposit Agreement, consent to) and, if applicable, request the Escrow Agent and Escrow Paying Agent to enter into (i) one or more
agreements supplemental to the Escrow Agreement, the NPA or the Deposit Agreement, for any of the purposes set forth in clauses (1) through (9) of such Section 9.01, and (without limitation of the foregoing or Section 9.01 of the
Basic Agreement) (a) clauses (2) and (3) of such Section 9.01 shall also be deemed to include the Company’s obligations under (in the case of clause (2)), and the Company’s rights and powers conferred by (in the
case of clause (3)), the NPA and any Participation Agreement, (b) references in clauses (4) and (6) of such Section 9.01 to “any Intercreditor Agreement or any Liquidity Facility” shall also be deemed to refer
to “the Intercreditor Agreement, the Class A Liquidity Facility, the Escrow Agreement, the NPA, any Participation Agreement or the Deposit Agreement”, and (c) references to “any Intercreditor Agreement or any Liquidity
Facility” in clause (7) of such Section 9.01 shall also be deemed to refer to “the Intercreditor Agreement, the NPA, any Indenture, the Class A Liquidity Facility, the Escrow Agreement, the Deposit Agreement or any
Participation Agreement”, (ii) one or more agreements supplemental to any Operative Agreement, the NPA, the Escrow Agreement or the Deposit Agreement to provide for the formation of one or more Additional Trusts in existence at any one
time, the issuance of one or more Classes of Additional Certificates from time to time, the purchase by any Additional Trust of applicable Additional Equipment Notes and other matters incidental thereto or as otherwise contemplated by
Section 2.01(b) of the Basic Agreement, all as provided in Section 4(a)(v) of the NPA and Section 8.01(d) of the Intercreditor Agreement, and (iii) one or more agreements supplemental to any Operative Agreement, the NPA, the
Escrow Agreement or the Deposit Agreement to provide for the formation of one or more Refinancing Trusts, the issuance of one or more Classes of Refinancing Certificates, the purchase by any Refinancing Trust of applicable Refinancing Equipment
Notes and other matters incidental thereto or as otherwise contemplated by Section 2.01(b) of the Basic Agreement, all as provided in Section 4(a)(v) of the NPA and Section 8.01(c) of the Intercreditor Agreement. In addition, the
following provisions of Section 9.01 of the Basic Agreement shall be amended, with respect to the Class A Trust, as follows: (A) Section 9.01(5) of the Basic Agreement shall be amended by inserting the phrase “(or to
facilitate any listing of any Certificates on any exchange or quotation system) or any requirement of DTC or like depositary,” after the phrase “any exchange or quotation system on which the Certificates of any series are listed” but
before the phrase “or of any regulatory body”; (B) Section 9.01(6) of the Basic Agreement shall be amended by inserting the phrase “to establish or” after the phrase “to such extent as shall be necessary” but
before the phrase “to continue”; and (C) Section 9.01(7) of the Basic Agreement shall be amended by replacing the phrase “and to add to or change” with the phrase “, or to evidence the substitution of a Liquidity
Provider with a Replacement Liquidity Provider or to provide for a Replacement Liquidity Facility or to incorporate appropriate mechanics for multiple instruments for a Replacement Liquidity Facility for a single Trust, all as provided in any
Intercreditor Agreement; or to evidence the substitution of a Depositary with a Replacement Depositary or to provide for a Replacement Deposit Agreement, all as provided in the NPA; or to evidence and provide for the acceptance of appointment by a
successor Escrow Agent or successor Escrow Paying Agent under the Escrow Agreement; or to provide multiple Liquidity Facilities with respect to one or more Trusts; or to add to or change”. 

Section 8.03 Supplemental Agreements with Consent of Class A Certificateholders. Without limitation of
Section 9.02 of the Basic Agreement, the provisions of Section 9.02 of the Basic Agreement shall apply to agreements or amendments for the purpose of adding any provisions to or changing in any manner or eliminating any of the provisions
of the Escrow Agreement, the Deposit Agreement, the Class A Liquidity Facility or the NPA or modifying in any manner the rights and obligations of the Class A Certificateholders under the Escrow Agreement, the Deposit Agreement, the
Class A Liquidity Facility or the NPA; provided that the provisions of Section 9.02(1) of the Basic Agreement shall be deemed to include reductions in any manner of, or delay in the timing of, any receipt by the Class A
Certificateholders of payments upon the Deposits. 

  

					
		  	22	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 Section 8.04 Consent of Trustees for Amendment of Section 6.01.
Notwithstanding any provision in Section 8.02 or Section 8.03 of this Trust Supplement to the contrary, no amendment or modification of Section 6.01 of this Trust Supplement shall be effective unless the trustee for each Class of
Certificates affected by such amendment or modification shall have consented thereto. 
 Section 8.05 Notice to Rating Agencies.
Promptly following its receipt of each amendment, consent, modification, supplement or waiver contemplated by this Article VIII, the Trustee shall send a copy thereof to each Rating Agency. 

ARTICLE IX 

MISCELLANEOUS PROVISIONS 

Section 9.01 Final Termination Date. The respective obligations and responsibilities of the Company and the Trustee created hereby
and the Class A Trust created hereby shall terminate upon the distribution to all Class A Certificateholders and the Trustee of all amounts required to be distributed to them pursuant to this Agreement and the disposition of all property
held as part of the Trust Property; provided, however, that in no event shall the Trust created hereby continue beyond the expiration of 21 years from the death of the last survivor of the descendants of Joseph P. Kennedy, Sr., the
father of John F. Kennedy, former President of the United States, living on the date of this Trust Supplement. 
 Notice of any termination
of the Class A Trust, specifying the applicable Regular Distribution Date (or applicable Special Distribution Date, as the case may be) upon which the Class A Certificateholders may surrender their Class A Certificates to the Trustee
for payment of the final distribution and cancellation, shall be mailed (or in the case of Global Certificates, sent electronically in accordance with DTC’s applicable procedures) promptly by the Trustee to the Class A Certificateholders
not earlier than 60 days and not later than 15 days preceding such final distribution. 
 Section 9.02 Basic Agreement Ratified.
Except and so far as herein expressly provided, all of the provisions, terms and conditions of the Basic Agreement are in all respects ratified and confirmed; and the Basic Agreement and this Trust Supplement shall be taken, read and construed as
one and the same instrument. To the extent that any provisions of the Basic Agreement are superseded by any provisions of this Trust Supplement, any reference to such provisions of the Basic Agreement herein or in the Basic Agreement shall be deemed
to be to such provisions of this Trust Supplement. 
 Section 9.03 Governing Law. THIS AGREEMENT HAS BEEN DELIVERED IN THE STATE
OF NEW YORK AND THIS AGREEMENT AND THE CLASS A CERTIFICATES SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAW OF THE STATE OF NEW YORK, INCLUDING ALL MATTERS OF CONSTRUCTION, VALIDITY AND PERFORMANCE. 

Section 9.04 Counterparts. This Trust Supplement may be executed in any number of counterparts (and each of the parties shall
not be required to execute the same counterpart). Each counterpart of this Trust Supplement including a signature page or pages executed by each of the parties hereto shall be an original counterpart of this Trust Supplement, but all of such
counterparts together shall constitute one instrument. 
 Section 9.05 Intention of Parties. The parties hereto intend that the
Class A Trust be classified for United States federal income tax purposes as a grantor trust under Subpart E, Part I, Subchapter J, Chapter 1 of Subtitle A of the Code, and not as a trust or association taxable as a corporation or as
a partnership. Each Certificateholder of, and each Person acquiring a beneficial interest in, a Class A Certificate, by its acceptance of its Class A Certificate or a beneficial interest therein, agrees to treat the Class A Trust as a
grantor trust for all United States federal, state and local income tax 

  

					
		  	23	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
purposes. The Trustee shall not be authorized or empowered to do anything that would cause the Class A Trust to fail to qualify as a grantor trust for such tax purposes (including as subject
to this restriction, acquiring any Aircraft by bidding the Equipment Notes relating thereto or otherwise, or taking any action with respect to any such Aircraft once acquired). 

Section 9.06 Submission to Jurisdiction. Each of the parties hereto, to the extent it may do so under applicable law, for purposes
hereof and of all other Operative Agreements hereby (i) irrevocably submits itself to the non-exclusive jurisdiction of the courts of the State of New York sitting in the City of New York and to the non-exclusive jurisdiction of the United States District Court for the Southern District of New York, for the purposes of any suit, action or other proceeding arising out of this Agreement, the subject matter hereof
or any of the transactions contemplated hereby brought by any party or parties hereto or thereto, or their successors or permitted assigns and (ii) waives, and agrees not to assert, by way of motion, as a defense, or otherwise, in any such
suit, action or proceeding, that the suit, action or proceeding is brought in an inconvenient forum, that the venue of the suit, action or proceeding is improper or that this Agreement or the subject matter hereof or any of the transactions
contemplated hereby may not be enforced in or by such courts. 
 Section 9.07 Successor and Assigns. All covenants, agreements,
representations and warranties in this Agreement by the Trustee and the Company shall bind and, to the extent permitted hereby, shall inure to the benefit of and be enforceable by their respective successors and assigns, whether so expressed or not.
Any request, notice, direction, consent, waiver or other instrument or action by any Class A Certificateholder shall bind the successors and assigns of such Class A Certificateholder. 

Section 9.08 Normal Commercial Relations. Anything contained in this Agreement to the contrary notwithstanding, the Trustee and
any Class A Certificateholder, or any bank or other Affiliate of any such party, may conduct any banking or other financial transactions, and have banking and other commercial relationships, with the Company fully to the same extent as if this
Agreement were not in effect, including without limitation the making of loans or other extensions of credit to the Company for any purpose whatsoever, whether related to any of the transactions contemplated hereby or otherwise. 

Section 9.09 No Recourse against Others. No past, present or future director, officer, employee, agent, member, manager, trustee
or stockholder, as such, of the Company or any successor Person shall have any liability for any obligations of the Company or any successor Person, either directly or through the Company or any successor Person, under the Class A Certificates
or this Agreement or for any claim based on, in respect of or by reason of such obligations or their creation, whether by virtue of any rule of law, statute or constitutional provision of by the enforcement of any assessment or by any legal or
equitable proceeding or otherwise. By accepting a Class A Certificate, each Class A Certificateholder agrees to the provisions of this Section 9.09 and waives and releases all such liability. Such waiver and release shall be part of
the consideration for the issue of the Class A Certificates. 
 [Remainder of Page Intentionally Blank; Signature Pages Follow]


  

					
		  	24	  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 IN WITNESS WHEREOF, the parties have caused this Trust Supplement to be duly executed by their
respective officers thereto duly authorized as of the date first written above. 
  

			
	SPIRIT AIRLINES, INC.
		
	By:	 	 /s/ Edward Christie

		 	Name: Edward Christie
		 	Title:   Executive Vice President and Chief             Financial Officer


 Signature Page 

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
			
	WILMINGTON TRUST, NATIONAL ASSOCIATION, as Trustee
		
	By:	 	 /s/ Jacqueline Solone

		 	Name: Jacqueline Solone
		 	Title: Vice President


 Signature Page 

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 EXHIBIT A to 

TRUST SUPPLEMENT NO. 2017-1A 

FORM OF CERTIFICATE 

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION
(“DTC”), TO THE TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IN EXCHANGE FOR THIS CERTIFICATE IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY
AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT HEREON IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY
PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.]* 

BY ITS ACQUISITION HEREOF, THE HOLDER REPRESENTS THAT EITHER (A) NO ASSETS OF A PLAN OR ANY TRUST ESTABLISHED WITH RESPECT TO A PLAN HAVE
BEEN USED TO PURCHASE OR HOLD THIS CERTIFICATE OR AN INTEREST HEREIN OR (B) THE PURCHASE AND HOLDING OF THIS CERTIFICATE OR INTEREST HEREIN BY SUCH A PERSON ARE EXEMPT FROM THE PROHIBITED TRANSACTION RESTRICTIONS OF ERISA AND THE CODE OR
PROVISIONS OF SIMILAR LAW PURSUANT TO ONE OR MORE PROHIBITED TRANSACTION STATUTORY OR ADMINISTRATIVE EXEMPTIONS OR SIMILAR EXEMPTIONS UNDER SIMILAR LAW. 

FURTHER, BY ITS ACQUISITION HEREOF, A HOLDER WHO IS AN ERISA PLAN REPRESENTS THAT THE DECISION TO ACQUIRE OR ACCEPT THIS CERTIFICATE OR
INTEREST HEREIN HAS BEEN MADE BY A DULY AUTHORITZED FIDUCIARY OF THE ERISA PLAN THAT (A) IS INDEPENDENT (AS THAT TERM IS USED IN 29 C.F.R. 2510-3-21(c)(1)) OF THE
COMPANY AND ITS AFFILIATES AND THERE IS NO FINANCIAL INTEREST, OWNERSHIP INTEREST, OR OTHER RELATIONSHIP, AGREEMENT OR UNDERSTANDING OR OTHERWISE THAT WOULD LIMIT ITS ABILITY TO CARRY OUT ITS FIDUCIARY RESPONSIBILITY TO THE ERISA PLAN; (B) IS A
BANK, INSURANCE CARRIER, REGISTERED INVESTMENT ADVISER, A REGISTERED BROKER-DEALER, OR AN INDEPENDENT FIDUCIARY THAT HOLDS, OR HAS UNDER MANAGEMENT OR CONTROL, TOTAL ASSETS OF AT LEAST $50 MILLION (IN EACH CASE, AS SPECIFIED IN 29 C.F.R. 2510.3-21(c)(1)(i)(A)-(E)); (C) IS CAPABLE OF EVALUATING INVESTMENT RISKS INDEPENDENTLY, BOTH IN GENERAL AND WITH REGARD TO PARTICULAR TRANSACTIONS AND INVESTMENT STRATEGIES (INCLUDING, WITHOUT LIMITATION, WITH
RESPECT TO THE DECISION TO ACQUIRE OR ACCEPT THIS CERTIFICATE OR INTEREST HEREIN); (D) HAS BEEN FAIRLY INFORMED THAT THE COMPANY AND ITS AFFILIATES HAVE NOT AND WILL NOT UNDERTAKE TO PROVIDE IMPARTIAL INVESTMENT ADVICE, OR TO GIVE ADVICE IN A
FIDUCIARY CAPACITY, IN CONNECTION WITH THE ACQUISITION OR ACCEPTANCE OF THIS CERTIFICATE OR INTEREST HEREIN; (E) HAS BEEN FAIRLY INFORMED 

 

	* 	 This legend to appear on Book-Entry Certificates to be deposited with The Depositary Trust Company.




  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
THAT THE COMPANY AND ITS AFFILIATES HAVE FINANCIAL INTERESTS IN THE ERISA PLAN’S ACQUISITION OR ACCEPTANCE OF THIS CERTIFICATE OR INTEREST HEREIN, WHICH INTERESTS MAY CONFLICT WITH THE
INTEREST OF THE ERISA PLAN, AS MORE FULLY DESCRIBED IN THE OFFERING MATERIALS; (F) IS A FIDUCIARY UNDER ERISA OR THE CODE, OR BOTH, WITH RESPECT TO THE DECISION TO ACQUIRE OR ACCEPT THIS CERTIFICATE OR INTEREST HEREIN AND IS RESPONSIBLE FOR
EXERCISING (AND HAS EXERCISED) INDEPENDENT JUDGMENT IN EVALUATING WHETHER TO INVEST THE ASSETS OF THE ERISA PLAN IN THIS CERTIFICATE OR INTEREST HEREIN; AND (G) IS NOT PAYING FOR THE COMPANY OR ANY OF ITS AFFILIATES, ANY FEE OR OTHER
COMPENSATION DIRECTLY FOR THE PROVISION OF INVESTMENT ADVICE (AS OPPOSED TO OTHER SERVICES) IN CONNECTION WITH THE ERISA PLAN’S ACQUISITION OR ACCEPTANCE OF THIS CERTIFICATE OR INTEREST HEREIN. 

CERTAIN TERMS USED IN THE FOREGOING PARAGRAPHS SHALL HAVE THE MEANINGS SPECIFIED IN THE AGREEMENT. 

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 [GLOBAL CERTIFICATE]† 
 SPIRIT AIRLINES PASS THROUGH TRUST 2017-1A 
 SPIRIT AIRLINES PASS THROUGH CERTIFICATE,
SERIES 2017-1A 
 Final Expected Regular Distribution Date: February 15, 2030 

evidencing a fractional undivided interest in the Trust, 

the property of which includes or will include, among  

other things, certain Equipment Notes each secured by 

an Aircraft owned by Spirit Airlines,
Inc.                      
  

					
	Certificate No.                     	  	$                     Fractional Undivided Interest representing 0.0012140931937935600% of the Trust per
$1,000 face amount	  	 CUSIP No. 84858X AA2
  

ISIN No. US84858XAA28


 THIS CERTIFIES THAT
                , for value received, is the registered owner of a
$                (                dollars) Fractional Undivided Interest (or such lesser
amounts as shall be the aggregate outstanding face amount hereof as set forth in the records of the Trustee) in the Spirit Airlines Pass Through Trust, Series 2017-1A (the “Trust”) created by
WILMINGTON TRUST, NATIONAL ASSOCIATION, as trustee (together with any successor in interest and any successor or other trustee appointed pursuant to the Trust Supplement referred to below, the “Trustee”) under a Pass Through Trust
Agreement, dated as of August 11, 2015 (the “Basic Agreement”), between Wilmington Trust, National Association and Spirit Airlines, Inc., a Delaware corporation (together with any successor in interest pursuant to Section 5.02 of
the Basic Agreement, the “Company”), as supplemented by Trust Supplement No. 2017-1A thereto dated as of November 28, 2017 (collectively with the Basic Agreement, and as may be amended from
time to time, the “Agreement”), between the Trustee and the Company, a summary of certain of the pertinent provisions of which is set forth below. To the extent not otherwise defined herein, the capitalized terms used herein have the
meanings assigned to them in the Agreement. This Certificate is one of the duly authorized Certificates designated as “Spirit Airlines Pass Through Certificates, Series 2017-1A” (herein called
the “Certificates”). This Certificate is issued under and is subject to the terms, provisions and conditions of the Agreement. By virtue of its acceptance hereof, the Certificateholder of this Certificate assents to and agrees to be bound
by all of the provisions of the Agreement and the Intercreditor Agreement, including the subordination provisions of Section 9.09 of the Intercreditor Agreement. The Trust Property is expected to include certain Equipment Notes and includes all
rights of the Trust and the Trustee, on behalf of the Trust, to receive any payments under the Intercreditor Agreement and the Class A Liquidity Facility. Each issue of the Equipment Notes will be secured by, among other things, a security
interest in the Aircraft owned by the Company. 
 The Certificates represent Fractional Undivided Interests in the Trust and the Trust
Property, and will have no rights, benefits or interest in respect of any other separate trust established pursuant to the terms of the Basic Agreement for any other series of certificates issued pursuant thereto. 

Subject to and in accordance with the terms of the Agreement and the Intercreditor Agreement, from funds then available to the Trustee, there
will be distributed on each February 15 and August 15 (each, a “Regular Distribution Date”), commencing on August 15, 2018, to the Person in whose name this Certificate is registered at the close of business on the 15th day
preceding the Regular Distribution Date, an amount in respect of the Scheduled Payments on the Series A Equipment Notes due on such Regular Distribution Date, the receipt of which has been confirmed by the Trustee, equal to the 

 

	† 	 To be included on the face of each Global Certificate.




  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
product of the percentage interest in the Trust evidenced by this Certificate and an amount equal to the sum of such Scheduled Payments. Subject to and in accordance with the terms of the
Agreement and the Intercreditor Agreement, in the event that Special Payments on the Series A Equipment Notes are received by the Trustee, from funds then available to the Trustee, there shall be distributed on the applicable Special Distribution
Date, to the Person in whose name this Certificate is registered at the close of business on the 15th day preceding the applicable Special Distribution Date, an amount in respect of such Special Payments on the Series A Equipment Notes, the receipt
of which has been confirmed by the Trustee, equal to the product of the percentage interest in the Trust evidenced by this Certificate and an amount equal to the sum of such Special Payments so received. If a Regular Distribution Date or Special
Distribution Date is not a Business Day, distribution shall be made on the immediately following Business Day and no interest shall accrue during the intervening period. The Trustee shall mail (or in the case of Global Certificates, send
electronically in accordance with DTC’s applicable procedures) notice of each Special Payment and the Special Distribution Date therefor to the Certificateholder of this Certificate. 

Distributions on this Certificate will be made by the Trustee by check mailed to the Person entitled thereto, without the presentation or
surrender of this Certificate or the making of any notation hereon, except that with respect to Certificates registered on the Record Date in the name of a Clearing Agency (or its nominee), such distributions shall be made by wire transfer. Except
as otherwise provided in the Agreement and notwithstanding the above, the final distribution on this Certificate will be made after notice mailed (or in the case of Global Certificates, sent electronically in accordance with DTC’s applicable
procedures) by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate at the office or agency of the Trustee specified in such notice. 

The Certificates do not represent a direct obligation of, or an obligation guaranteed by, or an interest in, the Company, the Trustee, the
Subordination Agent, any Loan Trustee or any Affiliate of any thereof. The Certificates are limited in right of payment, all as more specifically set forth on the face hereof and in the Agreement. All payments or distributions made to
Certificateholders under the Agreement shall be made only from the Trust Property and only to the extent that the Trustee shall have sufficient income or proceeds from the Trust Property to make such payments in accordance with the terms of the
Agreement. Each Certificateholder of this Certificate, by its acceptance hereof, agrees that it will look solely to the income and proceeds from the Trust Property to the extent available for any payment or distribution to such Certificateholder
pursuant to the terms of the Agreement and that it will not have any recourse to the Company, the Trustee, the Loan Trustees or any Affiliate of any thereof except as otherwise expressly provided in the Agreement, in any Note Document or in the
Intercreditor Agreement. This Certificate does not purport to summarize the Agreement and reference is made to the Agreement for information with respect to the interests, rights, benefits, obligations, proceeds and duties evidenced hereby. A copy
of the Agreement may be examined during normal business hours at the principal office of the Trustee, and at such other places, if any, designated by the Trustee, by any Certificateholder upon request. 

The Agreement permits, with certain exceptions therein provided, the amendment thereof, and the modification of the rights and obligations of
the Company and the rights of the Certificateholders under the Agreement, at any time by the Company and the Trustee with the consent of the Certificateholders holding Certificates evidencing Fractional Undivided Interests aggregating not less than
a majority in interest in the Trust. Any such consent by the Certificateholder of this Certificate shall be conclusive and binding on such Certificateholder and upon all future Certificateholders of this Certificate and of any Certificate issued
upon the transfer hereof or in exchange hereof or in lieu hereof whether or not notation of such consent is made upon this Certificate. The Agreement also permits the amendment thereof, in certain limited circumstances, without the consent of the
Certificateholders of any of the Certificates. 

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 As provided in the Agreement and subject to certain limitations set forth therein, the transfer
of this Certificate is registrable in the Register upon surrender of this Certificate for registration of transfer at the offices or agencies maintained by the Trustee in its capacity as Registrar, or by any successor Registrar, duly endorsed or
accompanied by a written instrument of transfer in form satisfactory to the Trustee and the Registrar, duly executed by the Certificateholder hereof or such Certificateholder’s attorney duly authorized in writing, and thereupon one or more new
Certificates of authorized denominations evidencing the same aggregate Fractional Undivided Interest in the Trust will be issued to the designated transferee or transferees. 

The Certificates are issuable only as registered Certificates without coupons in minimum denominations of $2,000 (or such other denomination
that is the lowest integral multiple of $1,000 that is, at the time of issuance, equal to at least 1,000 euros) Fractional Undivided Interest and integral multiples of $1,000 in excess thereof except that one Certificate may be issued in a different
denomination. As provided in the Agreement and subject to certain limitations therein set forth, the Certificates are exchangeable for new Certificates of authorized denominations evidencing the same aggregate Fractional Undivided Interest in the
Trust, as requested by the Certificateholder surrendering the same. 
 No service charge will be made for any such registration of transfer
or exchange, but the Trustee shall require payment of a sum sufficient to cover any tax or governmental charge payable in connection therewith. 

The Company, the Trustee, the Registrar and any Paying Agent shall deem and treat the Person in whose name this Certificate is registered as
the owner hereof for all purposes, and none of the Company, the Trustee, the Registrar or any such agent shall be affected by any notice to the contrary. 

Each Certificateholder and Person with a beneficial interest herein, by its acceptance of this Certificate or such interest, agrees to treat
the Trust as a grantor trust for all U.S. federal, state and local income tax purposes. 
 The obligations and responsibilities created by
the Agreement and the Trust created thereby shall terminate upon the distribution to Certificateholders of all amounts required to be distributed to them pursuant to the Agreement and the disposition of all property held as part of the Trust
Property. 
 Any Person acquiring or accepting this Certificate or an interest herein will, by such acquisition or acceptance, be deemed to
(a) represent and warrant to the Company, the Loan Trustees and the Trustee that either: (i) no assets of a Plan or any trust established with respect to a Plan have been used to purchase or hold this Certificate or an interest herein or
(ii) the purchase and holding of this Certificate or interest herein by such Person are exempt from the prohibited transaction restrictions of ERISA and the Code or provisions of Similar Law pursuant to one or more prohibited transaction
statutory or administrative exemptions or similar exemptions under Similar Law and (b) direct the Trustee to invest the assets held in the Trust pursuant to, and take all other actions contemplated by, the terms and conditions of the Basic
Agreement, this Trust Supplement, the Intercreditor Agreement, the Deposit Agreement, the Escrow Agreement, the NPA, and each Participation Agreement. 

Any Person who is an ERISA Plan and is acquiring or accepting this Certificate or an interest herein will, by such acquisition or acceptance,
be deemed to represent and warrant to the Company, the Loan Trustees and the Trustee that the decision to acquire or accept this Certificate or interest herein has been made by a duly authorized fiduciary of the ERISA Plan that (i) is
independent (as that term is used in 29 C.F.R. 2510.3-21(c)(1)) of the Company and its Affiliates and there is no financial interest, ownership interest, or other relationship, agreement or understanding or
otherwise that would limit its ability to carry out its fiduciary responsibility to the ERISA Plan; (ii) is a bank, insurance carrier, registered investment adviser, a registered broker-dealer, or an independent fiduciary that holds, or has
under management or control, total assets of at least $50 million (in each case, as specified in 29 C.F.R. 

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
2510.3-21(c)(1)(i)(A)-(E)); (iii) is capable of evaluating investment risks independently, both in general and with regard to particular transactions and
investment strategies (including, without limitation, with respect to the decision to acquire or accept this Certificate or interest herein); (iv) has been fairly informed that the Company and its Affiliates have not and will not undertake to
provide impartial investment advice, or to give advice in a fiduciary capacity, in connection with the acquisition or acceptance of this Certificate or interest herein; (v) has been fairly informed that the Company and its Affiliates have
financial interests in the ERISA Plan’s acquisition or acceptance of this Certificate or interest herein, which interests may conflict with the interest of the ERISA Plan, as more fully described in the offering materials; (vi) is a
fiduciary under ERISA or the Code, or both, with respect to the decision to acquire or accept this Certificate or interest herein and is responsible for exercising (and has exercised) independent judgment in evaluating whether to invest the assets
of the ERISA Plan in this Certificate or interest herein; and (vii) is not paying the Company or any of its Affiliates, any fee or other compensation directly for the provision of investment advice (as opposed to other services) in connection
with the ERISA Plan’s acquisition or acceptance of this Certificate or interest herein. 
 THIS CERTIFICATE AND THE AGREEMENT SHALL
BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAW OF THE STATE OF NEW YORK, INCLUDING ALL MATTERS OF CONSTRUCTION, VALIDITY AND PERFORMANCE. 

Unless the certificate of authentication hereon has been executed by the Trustee, by manual signature, this Certificate shall not be entitled
to any benefit under the Agreement or be valid for any purpose. 
  

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 IN WITNESS WHEREOF, the Trustee has caused this Certificate to be duly executed. 

 

			
	 SPIRIT AIRLINES PASS THROUGH TRUST
 2017-1A

		
	By:	 	 WILMINGTON TRUST, NATIONAL ASSOCIATION,
 as
Trustee

		
	By:	 	  

		 	Title:


 Dated: 

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 TRUSTEE’S CERTIFICATE OF AUTHENTICATION 

This is one of the Certificates referred to in the within-mentioned Agreement. 

 

			
	 WILMINGTON TRUST, NATIONAL ASSOCIATION,

as Trustee

		
	By:	 	  

		 	Authorized Officer



  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 [FORM OF TRANSFER NOTICE] 

FOR VALUE RECEIVED the undersigned registered holder hereby sell(s), assign(s) and transfer(s) unto 

Insert Taxpayer Identification No. 
  

                       
                                

Please print or typewrite name and address including zip code of assignee 
  

                       
                                

the within Certificate and all rights thereunder, hereby irrevocably constituting and appointing
                                         
    attorney to transfer said Certificate on the books of the Trustee with full power of substitution in the premises. 
  

			
	 Date:
                                         
                       
	  	                                      
                          
		  	NOTICE: The signature to this assignment must correspond with the name as written upon the face of the within-mentioned instrument in every particular, without alteration or any change whatsoever.
		
		  	SIGNATURE GUARANTEE: _______________

 Signatures must be guaranteed by an “eligible guarantor institution” meeting the requirements of the
Registrar, which requirements include membership or participation in the Security Transfer Agent Medallion Program (“STAMP”) or such other “signature guarantee program” as may be determined by the Registrar in addition to, or in
substitution for, STAMP, all in accordance with the Securities Exchange Act of 1934, as amended. 

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 EXHIBIT B to 

TRUST SUPPLEMENT NO. 2017-1A 

DTC LETTER OF REPRESENTATIONS 

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 EXHIBIT C to 

TRUST SUPPLEMENT NO. 2017-1A 

AMENDMENTS TO BASIC AGREEMENT 
 Part A

 Section 5.02. Consolidation, Merger, Etc. The Company shall not consolidate with or merge into any other
Person or convey, transfer or lease substantially all of its assets as an entirety to any Person, unless: 
 (i) the
successor or transferee entity shall, if and to the extent required under Section 1110 in order that any Loan Trustee continues to be entitled to any benefits of Section 1110 with respect to any Aircraft, be a holder of an air carrier
operating certificate issued by the Secretary of Transportation pursuant to Chapter 447 of Title 49 of the United States Code for aircraft capable of carrying ten or more individuals or 6,000 pounds or more of cargo, and shall execute and deliver to
the Trustee an agreement containing the express assumption by such successor or transferee entity of the due and punctual performance and observance of each covenant and condition of the Note Documents, the NPA and this Agreement to be performed or
observed by the Company; and 
 (ii) the Company shall deliver to the Trustee a certificate signed by a Responsible Officer
of the Company stating that such consolidation, merger, conveyance, transfer or lease and the assumption agreement mentioned in clause (i) above comply with this Section 5.02. 

Upon any consolidation or merger, or any conveyance, transfer or lease of substantially all of the assets of the Company as an
entirety in accordance with this Section 5.02, the successor Person formed by such consolidation or into which the Company is merged or to which such conveyance, transfer or lease is made shall succeed to, and be substituted for, and may
exercise every right and power of, the Company under the Note Documents, the NPA and this Agreement with the same effect as if such successor Person had been named as the Company herein. 

Part B 
 Section 6.07.
Certificateholders May Not Bring Suit Except Under Certain Conditions. A Certificateholder of any series shall not have the right to institute any suit, action or proceeding at law or in equity or otherwise with respect to this Agreement, the
related Trust Supplement or the Certificates or otherwise, or for the appointment of a receiver or for the enforcement of any other remedy under this Agreement, the related Trust Supplement or the Certificates or otherwise, unless: 

 

	 	(1)	such Certificateholder previously shall have given written notice to the Trustee of a continuing Event of Default; 

  

	 	(2)	Certificateholders holding Certificates of such series evidencing Fractional Undivided Interests aggregating not less than 25% of the related Trust shall have requested the Trustee in writing to institute such action,
suit or proceeding and shall have offered to the Trustee indemnity as provided in Section 7.03(e); 


  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)










	 	(3)	the Trustee shall have refused or neglected to institute any such action, suit or proceeding for 60 days after receipt of such notice, request and offer of indemnity; and 


 

	 	(4)	no Direction inconsistent with such written request shall have been given to the Trustee during such 60-day period by either Certificateholders holding Certificates of such series
evidencing Fractional Undivided Interests aggregating not less than a majority in interest in the related Trust or the Controlling Party under the related Intercreditor Agreement. 


Except to the extent provided in any applicable Intercreditor Agreement or in any applicable Trust Supplement, it is understood
and intended that no one or more of the Certificateholders of any series shall have any right in any manner whatsoever hereunder or under the related Trust Supplement or under the Certificates of such series to (i) surrender, impair, waive,
affect, disturb or prejudice any property in the Trust Property of the related Trust, or the lien of any related Indenture on any property subject thereto, or the rights of the Certificateholders of such series or the holders of the related
Equipment Notes, (ii) obtain or seek to obtain priority over or preference with respect to any other such Certificateholder of such series or (iii) enforce any right under this Agreement, the related Trust Supplement or under the
Certificates of such series, except in the manner provided in this Agreement and for the equal, ratable and common benefit of all the Certificateholders of such series. 

Part C 
 Provided that
there is a bank or trust company in a U.S. jurisdiction where there are no Avoidable Taxes that is willing to act as Trustee and is eligible to act as Trustee under Section 7.08 and the applicable provisions of any Trust Supplement, the Company
shall promptly appoint a successor Trustee of such Trust in a jurisdiction where there are no Avoidable Taxes. 
 Part D 

(a) file with the Trustee, within 30 days after the Company files the same with the SEC, copies of the annual reports and of
the information, documents and other reports (or copies of such portions of any of the foregoing as the SEC may from time to time by rules and regulations prescribe) which the Company is required to file with the SEC pursuant to Section 13 or
Section 15(d) of the Securities Exchange Act of 1934, as amended; or, if the Company is not required to file information, documents or reports pursuant to either of such sections, then to file with the Trustee and the SEC, in accordance with
rules and regulations prescribed by the SEC, such supplementary and periodic information, documents and reports which may be required pursuant to Section 13 of the Securities Exchange Act of 1934, as amended, in respect of a security listed and
registered on a national securities exchange as may be prescribed in such rules and regulations; 
 Part E 

(4) (A) to cure any ambiguity or to correct any mistake or inconsistency contained in this Basic Agreement or in any related
Trust Supplement, any Intercreditor Agreement or any Liquidity Facility; or (B) to make or modify any other provision in regard to matters or questions arising under this Basic Agreement or any related Trust Supplement, any Intercreditor
Agreement or any Liquidity Facility as the Company may deem necessary or desirable and that will not materially adversely affect the interests of the related Certificateholders; or (C) to correct or


  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 
supplement the description of any property constituting property of any Trust or the description of any Aircraft, and to reflect the substitution of another aircraft for any Aircraft; or 

Part F 

Section 12.01. Limitation on Rights of Certificateholders. (a) The insolvency, death or incapacity of any
Certificateholder of any series shall not operate to terminate this Agreement or the related Trust, nor entitle such Certificateholder’s legal representative or heirs to claim an accounting or to take any action or commence any proceeding in
any court for a partition or winding up of the Trust, nor otherwise affect the rights, obligations and liabilities of the parties hereto or any of them. No Certificateholder of any series shall be entitled to revoke the related Trust. 

(b) No transfer, by operation of law or otherwise, of any Certificate or other right, title and interest of any
Certificateholder in and to the applicable Trust Property or under the related Trust shall operate to terminate the Trust or entitle such Certificateholder or any successor or transferee of such Certificateholder to an accounting or to the transfer
to it of legal title to any part of such Trust Property. 
 Part G 

Section 12.02. Liabilities of Certificateholders. The Certificateholders of each series shall not be personally
liable for obligations of the related Trust, the Fractional Undivided Interests represented by the Certificates of such series shall be nonassessable for any losses or expenses of such Trust or for any reason whatsoever, and the Certificates of such
series upon authentication thereof by the Trustee pursuant to Section 3.02 are and shall be deemed fully paid. No Certificateholder of such series shall have any right (except as expressly provided herein) to vote or in any manner otherwise
control the operation and management of the related Trust Property, the related Trust, or the obligations of the parties hereto, nor shall anything set forth herein, or contained in the terms of the Certificates of such series, be construed so as to
constitute the Certificateholders of such series from time to time as partners or members of an association. 

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 SCHEDULE I to 

TRUST SUPPLEMENT NO. 2017-1A 

SERIES A EQUIPMENT NOTES, 

PRINCIPAL AMOUNTS, MATURITIES AND AIRCRAFT 
  

									
	 Initial Principal

Amount of Series

A Equipment

Notes*
	 	  	 Maturity
	  	 Aircraft**
	  	 Manufacturer Serial

Number**

	 	$ 6,258,000	 	  	February 15, 2030	  	A320-200	  	8018
	 	6,258,000	 	  	February 15, 2030	  	A320-200	  	8021
	 	6,272,000	 	  	February 15, 2030	  	A320-200	  	8012
	 	7,641,000	 	  	February 15, 2030	  	A321-200	  	8114
	 	7,641,000	 	  	February 15, 2030	  	A321-200	  	8047
	 	7,641,000	 	  	February 15, 2030	  	A321-200	  	8115
	 	7,647,000	 	  	February 15, 2030	  	A321-200	  	8141
	 	7,647,000	 	  	February 15, 2030	  	A321-200	  	8160
	 	6,321,000	 	  	February 15, 2030	  	A320-200	  	8176
	 	6,335,000	 	  	February 15, 2030	  	A320-200	  	TBD
	 	6,335,000	 	  	February 15, 2030	  	A320-200	  	TBD
	 	6,370,000	 	  	February 15, 2030	  	A320-200	  	TBD

  

	*	Subject to adjustment as provided in the NPA. 


	**	Subject to substitution as provided in the NPA. 


  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)









 SCHEDULE II to 

TRUST SUPPLEMENT NO. 2017-1A 

NOTE DOCUMENTS 

Participation Agreement 
 Indenture

 Airframe Warranties Agreement (as defined in any applicable Indenture) 

For each of the aircraft listed in Schedule I. 

  

					
		  		  	 Trust Supplement No. 2017-1A

(Spirit 2017-1 EETC)