Neither of the engines for Falcon or IL-2 are old, it's just a case of how many different ways can you package an air combat sim?
For WWII:
Aces High 1 & II, Air Warrior (defunct), War Birds I, II, III, Jane's, IL-2, etc
Jets:
Mig Ally Ace, F-15 Strike Eagle, F-15, Falcon, Falcon 2.0...