FORM 4 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
1. Name and Address of Reporting Person *
MADISON DEARBORN PARTNERS LLC

(Last) (First) (Middle)
C/O MADISON DEARBORN PARTNERS, LLC
70 W. MADISON STREET, SUITE 4600

(Street)
CHICAGO IL 60602

(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
AEVEX Corp. [ AVEX ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director X 10% Owner
Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
06/05/2026
4. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
Form filed by One Reporting Person
X Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V Amount (A) or (D) Price
Class A Common Stock 06/05/2026   S (1)   2,273,843 D $ 25.99 22,861,457 I See footnotes. (2) (3)
Class A Common Stock 06/05/2026   J (1)   2,611 D (1) 22,858,846 I See footnotes. (2) (3)
Class B Common Stock 06/05/2026   D (4)   4,757,448 D (4) 58,540,076 I See footnotes. (3) (5)
Class B Common Stock 06/05/2026   J (4)   975,246 D (4) 57,564,830 I See footnotes. (3) (5)
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Series B Units (6) 06/05/2026   D (4)     4,757,448   (6)   (6) Class A Common Stock 4,757,448 (4) 58,540,076 I See footnotes. (3) (5)
Series B Units (6) 06/05/2026   J (4)     975,246   (6)   (6) Class A Common Stock 975,246 (4) 57,564,830 I See footnotes. (3) (5)
Explanation of Responses:
1. In connection with the offering as described in the Issuer's Registration Statement on Form S-1 (Registration No. 333-296396) (the "Offering"), the following transactions have occurred regarding this Statement's reported Class A common stock of the Issuer ("Class A Shares"): (i) ATS PubCo Holdings, L.P. ("ATS PubCo Holdings") sold 9,341 Class A Shares and ATS PubCo Seller Holdings, LLC sold 2,264,502 Class A Shares to the underwriters at a net offering price of $25.99 and (ii) ATS PubCo Holdings distributed 2,611 Class A Shares in a pro rata distribution to its limited partners for no consideration.
2. Following the transactions discussed in footnote 1, (i) ATS PubCo Holdings directly holds 22,694,184 Class A Shares and (ii) ATS Management Holdings, LLC ("ATS Management Holdings") directly holds 164,662 Class A Shares. Both ATS PubCo Holdings and ATS Management Holdings are controlled by Madison Dearborn Capital Partners VII-B, L.P., Madison Dearborn Capital Partners VII Executive-B, L.P. and Madison Dearborn Capital Partners VII-C, LP (collectively, the "MDP Funds").
3. The ultimate general partner of each of the MDP Funds is Madison Dearborn Partners, LLC. Paul J. Finnegan and Vahe A. Dombalagian are the sole members of the board of managers of Madison Dearborn Partners, LLC, which has the power to vote or dispose of the securities held by the MDP Funds. By virtue of the relationships described herein, each of the reporting persons may be deemed to beneficially own the securities reported hereby. Each of the reporting persons disclaims beneficial ownership of the securities except to the extent of its pecuniary interest therein.
4. In connection with the Offering, the following transactions have occurred regarding this Statement's reported Class B common stock of the Issuer ("Class B Shares") and Series B Units of Athena Technology Solutions Holdings, LLC ("Series B Units"): (i) ATS Investment Holdings, LLC ("ATS Investment Holdings") distributed 5,732,694 Class B Shares and corresponding Series B Units in a pro rata distribution to its members, including certain entities controlled by the MDP Funds, for no consideration and (ii) following such distribution, the MDP Funds sold 4,757,448 Series B Units, received by such entities controlled by the MDP Funds in such distribution, at a net offering price of $25.99 per unit to the Issuer (together with the corresponding Class B Shares for no additional consideration).
5. Following the transactions discussed in footnote 4, (i) ATS Investment Holdings directly holds 57,153,106 Class B Shares and corresponding Series B Units and (ii) ATS Management Holdings directly holds 411,724 Class B Shares and corresponding Series B Units. Both ATS Investment Holdings and ATS Management Holdings are controlled by the MDP Funds.
6. Series B Units are exchangeable (together with an equal number of Class B Shares) for Class A Shares on a one-for-one basis. Series B Units do not expire.
/s/ Katherine M. Bryan, Director, Associate General Counsel and Chief Compliance Officer of Madison Dearborn Partners, LLC 06/05/2026
** Signature of Reporting Person Date
/s/ Katherine M. Bryan, Director, Associate General Counsel and Chief Compliance Officer of the General Partner of the General Partner of Madison Dearborn Capital Partners VII-B, L.P. 06/05/2026
** Signature of Reporting Person Date
/s/ Katherine M. Bryan, Director, Associate General Counsel and Chief Compliance Officer Managing Director of the General Partner of the General Partner of Madison Dearborn Capital Partners VII Executive-B, L.P. 06/05/2026
** Signature of Reporting Person Date
/s/ Katherine M. Bryan, Director, Associate General Counsel and Chief Compliance Officer Managing Director of the General Partner of the General Partner of Madison Dearborn Capital Partners VII-C, LP 06/05/2026
** Signature of Reporting Person Date
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