My first thought is that most plane designations come from the military. P-51, F4U, etc were not designations from the company - they were military designations. I suspect it is the same in other countries. Il-2 is the Soviet designation for plane type 2 from the Ilyushin design bureau. If anybody owns the right to the designation, it is the respective governments.
Not sure about the names, although I know of recent cases of U.S. equipment where the manufacturer's name was rejected. Don't know if the manufacturer came up with a new one or the military designated one. In either case, I doubt the name was trademarked or copyrighted - especially in the 1940s.
A virtual representation of an aircraft would not violate any patents since no actual part or process was produced or used. Performance data would certainly be public domain.
The only place I could see a potential valid point is in the use of the company name in association with a piece of equipment. If HTC says the Aces High F4U Corsair is armed with Browning .50 cal machine guns, I guess he could, in some narrow-minded, money-hungry corporate lawyer's mind, be using the Browning name to turn a profit. I sure the legallese would be:
the Aces High virtual F4U Corsair (not in any way associated with Northrop - Grumman, its subsidiaries, or any company, past or present, who designed, built, or serviced real F4U Corsairs), uses virtual .50 cal machine guns whose performance is based on historical data for .50 cal machine guns in use by the U.S. Navy for carrier based aircraft at the time.
