Light Flyer
Beat the game with the normal ending in Limit 500 or Unlimited modes.
Leo Copter
Beat the game with the good ending in Unlimited, Mirror or Reverse modes.
Foo Fighter
Beat the game with the Light Flyer and Leo Copter in Unlimited, Mirror or Reverse modes.
The Fly
Beat the game with the Foo Fighter in Unlimited, Mirror or Reverse modes + destroy all the balloons in the bonus level.