Humm I see.

I guess than a good idea in case Boeing doesn't give you permission is the use this name

"AH-64" or even "AH-64D"

but without the name "Apache", this way if you don't use the "AH-64 Apache" name which is trademarked under "Goods and services: Helicopters" you shoudn't have any problems at all.

I hope that Boeing gives you the permission but you should be ready in case you don't get Boeing's permission and in case this happens (I hope not) that you please don't give up! Afterall there are tons of games (from every possible genre) out there that use the Apache and other helicopters and don't get sued (and I doubt that in the vast majority of these cases that permission was ever ask to aerospace companies).