You better be Giving the USA the Block 3 FA/18 for this Reason

Matching vehicles based purely off of some kind of introductory/testing date would cause many issues.

By-date match making has been discussed at length in virtually any historic-matchmaking thread.

Originally posted by Super Pleb: With all this being said why didn't you give the USA the F15 C which is the publicly known older brother of the F 15 J ? The facts will eventually overcome you.

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The American F-15A in game is an F-15A MSIP.... Not from 1976, but from 1983.
The American F-15E was under construction in 1985... But was introduced later, in 1988.
The Japanese F-15J is not the initial version introduced in 1981. The skin that the 15J wears belongs to 204th Squadron, which only started to have 15J's in 1984.

The F-15C/Early would be very similar to MSIP F-15A. Yes, the C can fire AIM-120's, but, so can the Gripen-C, and AV-8+ (Which, currently don't have that ability in game, neither would the C).

The Gripen-A and Gripen-C are different aircraft, and while the C is the newer aircraft.... The weapons available to either make them approximately equal in terms of performance in game.

As mentioned by another above, the "2000's Su-27" is a T-10S, also from the early 1980's.

As for US aircraft dates, the US F-16A Block 15/ADF & F-16C Block 50 are from 1989 and 1991 respectively.