As game play begins, you will see parachutes with icons attached dropping into the arena.
Learn the icons and their colors! Each offers specific help, with the exception of the mystery (?) parachute, which provides random supplies/assistance.
In addition to re-supplying your plane with rockets, chaff, and smoke screen, you will find icons that give you:
Speed Boost (for those planes capable of using it)
Armor Penetrating Bullets;
Sniper View (allows you to zoom in on the action);
Gold medallions (either found on island or floating down with parachutes) allow you to change your plane model (depending on what you have earned/purchased on the Hangar screen).