From October 1984 to June 1985 he learned to fly the F-4D Phantom II at Homestead Air Force Base in Florida with the 308th Fighter Squadron.

[3] Returning to the United States, Post became an F-16 Falcon evaluation pilot with the 62nd and 63rd Fighter Squadrons at MacDill Air Force Base in Florida.

[3] This was the beginning of a long association with the F-16, which would eventually see him complete over 4,000 hours flight time in the aircraft when he flew his 2,565th sortie in March 2011.

From August 2012 until June 2013, he was Deputy Director of Operations, Plans and Policy at Headquarters Pacific Air Forces at Joint Base Pearl Harbor–Hickam in Hawaii.

From June 2013 until September 2014, he was Director of Operations at Headquarters, Air Combat Command at Joint Base Langley-Eustis in Virginia with the rank of brigadier general from August 2013.

At the Air Force's annual Weapons and Tactics Conference on 10 January 2015, Post responded to a question about the future of the Fairchild Republic A-10 Thunderbolt II.

[10] Post recalled that in his answer he said:I believed it was essential for the members in the audience to listen and understand the importance of the Air Force's decision with respect to the future of the A-10.

I said I could relate with those passionate about their assigned weapon system, but unfortunately fiscal reality wouldn't allow us to do both-continue flying the A-10 while bringing the F-35 to operational capability.

I said It was time to focus and work hard towards doing the best we can with what we know, and not towards undermining senior leaders' decisions, nor towards fulfilling personal preferences and agendas.

On 13 January, he notified the Chief of Staff of the United States Air Force, General Mark Welsh of what he had said in an email.

[7] On 16 January 2015, the Office of the Inspector General, U.S. Department of Defense received an anonymous complaint alleging that Post had made remarks to the effect that communicating with Congress about the capabilities of the A-10 was treason.

Meanwhile, on 21 January,[6] the United States Secretary of the Air Force, Deborah Lee James,[7] received a letter of complaint from Senator John McCain.