X0306 4 2017-06-06 1 0000894081 Air Transport Services Group, Inc. ATSG 0001374566 MESDAG WILLEM C/O RED MOUNTAIN CAPITAL PARTNERS LLC 10100 SANTA MONICA BOULEVARD, SUITE 925 LOS ANGELES CA 90067 0 0 0 1 Please refer to Remarks below 0001374603 RED MOUNTAIN PARTNERS, L.P. 10100 SANTA MONICA BOULEVARD SUITE 925 LOS ANGELES CA 90067 0 0 1 0 0001374588 RED MOUNTAIN CAPITAL PARTNERS LLC 10100 SANTA MONICA BOULEVARD SUITE 925 LOS ANGELES CA 90067 0 0 0 1 Please refer to Remarks below 0001374606 RMCP GP LLC 10100 SANTA MONICA BOULEVARD SUITE 925 LOS ANGELES CA 90067 0 0 0 1 Please refer to Remarks below 0001374607 RED MOUNTAIN CAPITAL MANAGEMENT INC 10100 SANTA MONICA BOULEVARD SUITE 925 LOS ANGELES CA 90067 0 0 0 1 Please refer to Remarks below Common Stock 2017-06-06 4 S 0 4377330 22.42 D 2326108 I See footnote 3 and Remarks below In connection with a secondary offering of shares of common stock of Air Transport Services Group, Inc. (the "Common Stock") by Red Mountain Partners, L.P. ("RMP") pursuant to an underwriting agreement and prospectus supplement and accompanying prospectus, each dated May 31, 2017 (the "Secondary Offering"), RMP, as selling shareholder, sold 4,377,330 shares of Common Stock to Merrill Lynch, Pierce, Fenner & Smith Incorporated, as underwriter, at a price of $22.42 per share. The Secondary Offering closed on June 6, 2017. Each of the reporting persons hereunder ceased to be a beneficial owner of more than 10% of the Common Stock as of June 6, 2017, following the closing of the Secondary Offering. These shares are held by RMP. This Form 4 is jointly filed by (i) RMP, (ii) RMCP GP LLC ("RMCP GP"), (iii) Red Mountain Capital Partners LLC ("RMCP LLC"), (iv) Red Mountain Capital Management, Inc. ("RMCM"), and (v) Mr. Mesdag. RMCP GP is the general partner of RMP. RMCP LLC is the managing member of RMCP GP. RMCM is the managing member of RMCP LLC. Mr. Mesdag is the president, sole executive officer, sole director and sole shareholder of RMCM. Each of Mr. Mesdag, RMCM, RMCP LLC, and RMCP GP, by virtue of their direct or indirect control of RMP, may be deemed to beneficially own some or all of the securities reported as being held by RMP. Each of the reporting persons hereunder disclaims beneficial ownership of the reported securities except to the extent of its or his pecuniary interest therein. This Form 4 shall not be deemed to be an admission that any reporting person hereunder is the beneficial owner of any of the reported securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose. /s/ Willem Mesdag, on behalf of himself and each of the other reporting persons 2017-06-06