The military was at AGC after PIT, which had been a National Guard base from the 40's, opened as a commercial field. The army was at Roger's Field in Fox Chapel, then Bettis Field, then AGC, where an active duty army facility remained until maybe the very early 70's. They were in the lower west ramp, last large hangar on the right, and is still referred to as the "army hangar". They had their own gas pump, if I remember correctly. It is a maintenance hangar now.
There were fixed wing there and helicopters. I remember a newspaper article in the 60's, when after a light dusting of snow. a twin rotor helo was asked to fly the length of the main runway to blow the snow off.
Also the Navy had a regular round trip run every weekend with a DC-4, and later a DC-9. I saw the DC-4 (R4D) go off the runway once and start down the cliff, when a brake locked. The flights got moved to PIT when there was runway construction. I rode that DC-4 trip once-Norfolk to PIT, via Huntingdon, WVA 1972.