My first choice would be the BAe Hawk, but from what I heard it is not possiple because the team has no access to the airplane.

I'd like to see a slow, manouverable jet....aerobatic stuff. Maybe a F-5 Tiger.

I for one would LOVE to have some scripted AI planes following a given path trough the most common airshow manouvers, while the player has to stay with them in formation. That would be a real challenge.