The answer should be Texas.
Hitech and a small crew broke away from Warbirds in 1999?, when iEN bought the company and wanted to move all production to North Carolina. Hitech, Pyro, Waffle?, Superfly, NateDog?, Ronnie, and I forget who else - they all left the company and formed Hitech Creations, which produced Aces High in around 2000.
(If memory serves, I think this version is pretty close)
IIRC correctly Warbirds was originally produced by iMagic? And it was an outgrowth of some film camera code Hitech had created to run with a different air combat sim (the name escapes me) - but it had 3 countries, A, B, and C.
Warbirds had four countries - Red, Green, Gold, and Purple. And it had a rolling plane set, where at the start of each tour, only the early War aircraft were available. I think it took two weeks to get to the late-War aircraft?