Use the following steps to unlock all aircraft, including special colors. First, acquire an aircraft by destroying it in battle. This is easy, except for three aircraft. Forget the ground targets and dogfight instead, which is the true nature of an ace. You can acquire three different paint schemes for each aircraft. Two of the paint schemes can be acquired by destroying that color aircraft in battle. To acquire the special brightly colored third aircraft, you must find and kill the pilot flying it. On each level of the game there is a single hidden aircraft (eighteen total hidden aircraft). Each one of these aircraft has a specific pilot. When you see the aircraft in front of you and lock on, it will display the pilot's name next to the aircraft name and lock on square. For example, "S-37A SMIRNOVA". The hidden aircraft will not show up on radar until you get nearby. On radar, the aircraft will be marked with a red triangle instead of yellow. Each hidden aircraft is always in the same place on their specific level. This is always in an empty spot on the map away from the main combat zone. The aircraft can usually be found directly behind the main combat zone. Last but not least are the three remaining aircraft. To acquire the Yellow Squadron fighter (SU-37) of your nemesis Yellow-13, you must kill all of the pilots with names flying the special colored aircraft (eighteen total).