SCHEDULE 13G

CUSIP Number(s):

00835T107

1

Names of Reporting Persons

Madison Dearborn Partners LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 80,423,676.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 80,423,676.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

80,423,676.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

11

Percent of class represented by amount in row (9)

49.5 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: The reported amount includes 57,564,830 shares of Class A common stock ("Class A Common Stock") of the Issuer issuable upon conversion of Series B Units of Athena Technology Solutions Holdings, LLC ("Series B Units") (together with an equal number of Class B common stock ("Class B Common Stock") of the Issuer). The reported percentage is calculated based on 56,470,333 shares of Class A Common Stock outstanding as of August 12, 2026, as reported on the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 12, 2026, as increased by 57,564,830 shares of Class A Common Stock issuable upon conversion of Series B Units (together with an equal number of Class B Common Stock).

SCHEDULE 13G

CUSIP Number(s):

00835T107

1

Names of Reporting Persons

MADISON DEARBORN CAPITAL PARTNERS VII-B, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 80,423,676.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 80,423,676.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

80,423,676.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

11

Percent of class represented by amount in row (9)

49.5 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: The reported amount includes 57,564,830 shares of Class A common stock ("Class A Common Stock") of the Issuer issuable upon conversion of Series B Units of Athena Technology Solutions Holdings, LLC ("Series B Units") (together with an equal number of Class B common stock ("Class B Common Stock") of the Issuer). The reported percentage is calculated based on 56,470,333 shares of Class A Common Stock outstanding as of August 12, 2026, as reported on the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 12, 2026, as increased by 57,564,830 shares of Class A Common Stock issuable upon conversion of Series B Units (together with an equal number of Class B Common Stock).

SCHEDULE 13G

CUSIP Number(s):

00835T107

1

Names of Reporting Persons

MADISON DEARBORN CAPITAL PARTNERS VII EXECUTIVE-B, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 80,423,676.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 80,423,676.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

80,423,676.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

11

Percent of class represented by amount in row (9)

49.5 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: The reported amount includes 57,564,830 shares of Class A common stock ("Class A Common Stock") of the Issuer issuable upon conversion of Series B Units of Athena Technology Solutions Holdings, LLC ("Series B Units") (together with an equal number of Class B common stock ("Class B Common Stock") of the Issuer). The reported percentage is calculated based on 56,470,333 shares of Class A Common Stock outstanding as of August 12, 2026, as reported on the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 12, 2026, as increased by 57,564,830 shares of Class A Common Stock issuable upon conversion of Series B Units (together with an equal number of Class B Common Stock).

SCHEDULE 13G

CUSIP Number(s):

00835T107

1

Names of Reporting Persons

MADISON DEARBORN CAPITAL PARTNERS VII-C, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 80,423,676.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 80,423,676.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

80,423,676.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

11

Percent of class represented by amount in row (9)

49.5 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: The reported amount includes 57,564,830 shares of Class A common stock ("Class A Common Stock") of the Issuer issuable upon conversion of Series B Units of Athena Technology Solutions Holdings, LLC ("Series B Units") (together with an equal number of Class B common stock ("Class B Common Stock") of the Issuer). The reported percentage is calculated based on 56,470,333 shares of Class A Common Stock outstanding as of August 12, 2026, as reported on the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 12, 2026, as increased by 57,564,830 shares of Class A Common Stock issuable upon conversion of Series B Units (together with an equal number of Class B Common Stock).

SCHEDULE 13G

Item 1.

(a)

Name of issuer:

AEVEX Corp.

(b)

Address of issuer's principal executive offices:

440 Stevens Ave # 150 Solana Beach, CA 92075

Item 2.

(a)

Name of person filing:

This statement is being jointly filed by each of the persons below pursuant to Rule 13d-1(k) promulgated by the SEC pursuant to Section 13 of the Act, all of whom together are referred to herein as the "Reporting Persons": (i) Madison Dearborn Capital Partners VII-B, L.P.; (ii) Madison Deaborn Capital Partners VII Executive-B, L.P.; (iii) Madison Deaborn Capital Partners VII-C, L.P. (together with each of the foregoing, the "MDP Funds"); and (iv) Madison Dearborn Partners, LLC ("Madison Dearborn").

(b)

Address or principal business office or, if none, residence:

70 W. Madison Street, Suite 4600 Chicago, IL 60602

(c)

Citizenship:

See responses to row 4 on each cover page.

(d)

Title of class of securities:

Class A common stock, par value $0.0001 per share

(e)

CUSIP Number(s):

00835T107

Item 3.

If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

(a)

Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);

(b)

Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);

(c)

Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);

(d)

Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);

(e)

An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);

(f)

An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);

(g)

A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

(h)

A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i)

A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j)

A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:

(k)

Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).

Item 4.

Ownership

(a)

Amount beneficially owned:

See responses to row 9 on each cover page. The reported securities are directly held as follows: (i) ATS PubCo Holdings, L.P. ("ATS PubCo Holdings) directly holds 22,694,184 Class A Common Stock, (ii) ATS Management Holdings, LLC ("ATS Management Holdings") directly holds 164,662 Class A Common Stock and 411,724 Class B Common Stock and corresponding Series B Units which upon conversion will result in the issuance of an equivalent number of Class A Common Stock and (iii) ATS Investment Holdings, LLC ("ATS Investment Holdings") directly holds 57,153,106 Class B Common Stock and corresponding Series B Units which upon conversion will result in the issuance of an equivalent number of Class A Common Stock. Each of ATS PubCo Holdings, ATS Management Holdings and ATS Investment Holdings are controlled by the MDP Funds. The ultimate general partner of each of the MDP Funds is Madison Dearborn. Paul J. Finnegan and Vahe A. Dombalagian are the sole members of the board of managers of Madison Dearborn, 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 herein. Pursuant to Rule 13d-4 of the Act, the Reporting Persons declare that filing this statement shall not be construed as an admission that any of the Reporting Persons are, for the purposes of Section 13(d) and/or Section 13(g) of the Act, the beneficial owner of any securities covered by this statement, and such beneficial ownership is expressly disclaimed by the Reporting Persons.

(b)

Percent of class:

See responses to row 11 on each cover page.

(c)

Number of shares as to which the person has:

(i) Sole power to vote or to direct the vote:

See responses to row 5 on each cover page

(ii) Shared power to vote or to direct the vote:

See responses to row 6 on each cover page

(iii) Sole power to dispose or to direct the disposition of:

See responses to row 7 on each cover page

(iv) Shared power to dispose or to direct the disposition of:

See responses to row 8 on each cover page

Item 5.

Ownership of 5 Percent or Less of a Class.

Not Applicable

Item 6.

Ownership of more than 5 Percent on Behalf of Another Person.

Not Applicable

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

Not Applicable

Item 8.

Identification and Classification of Members of the Group.

Not Applicable

Item 9.

Notice of Dissolution of Group.

Not Applicable

Item 10.

Certifications:

Not Applicable

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Madison Dearborn Partners LLC

Signature:	/s/ Katherine M. Bryan
Name/Title:	Katherine M. Bryan, Director, Associate General Counsel and Chief Compliance Officer
Date:	08/14/2026

MADISON DEARBORN CAPITAL PARTNERS VII-B, L.P.

Signature:	/s/ Katherine M. Bryan
Name/Title:	Katherine M. Bryan, Director, Associate General Counsel and Chief Compliance Officer of the General Partner of the General Partner of Madison Dearborn
Date:	08/14/2026

MADISON DEARBORN CAPITAL PARTNERS VII EXECUTIVE-B, L.P.

Signature:	/s/ Katherine M. Bryan
Name/Title:	Katherine M. Bryan, Director, Associate General Counsel and Chief Compliance Officer of the General Partner of the General Partner of Madison Dearborn
Date:	08/14/2026

MADISON DEARBORN CAPITAL PARTNERS VII-C, L.P.

Signature:	/s/ Katherine M. Bryan
Name/Title:	Katherine M. Bryan, Director, Associate General Counsel and Chief Compliance Officer of the General Partner of the General Partner of Madison Dearborn
Date:	08/14/2026

Exhibit Information

Exhibit 99.1 Joint Filing Agreement, dated August 14, 2026