The big cargo plane is also from HAWX although it is only flown by the AI in that game.
I assume you modded the engines and tail, though... The aircraft looks a great deal like the AN-124 Ruslan (and I'm certain it is... unless it was actually a C-5...)
No, HAWX uses bastardized versions of certain real-life aircraft for NPC planes, modified so that they don't entirely resemble anything. The Antonov An-521 model is a modified An-225, the Tu-194 Bogan is a kitbash of a couple of different Tupolev bombers, and the C-45/VC-45 is an Airbus A330 with a different nose section, a modified tail, and more engines.
Could you put some turrets on those planes and make them uhh...gunships? 
No, turrets only appear on bombers. The gunships in Wings are all VTOLs and more resemble the AH-64 than the AC-130. Those aircraft are far too large for the AC-130's role anyway. The C-94K is 71 meters long and the An-521 is 82 meters.