Due to the pervasive record-keeping nature of the game's Pilot Feedback System, you should create a second "test pilot" as a guinea pig for dodgy missions or experimental flights. This way, your primary on-screen persona can advance through the ranks more quickly and not have to make up for the thousands of negative points that failed missions and destroyed aircraft can generate (even in Training mode).
Wingmen
When entering into a furball with a flight of enemy planes, use your wingmen as much as possible. By issuing regular commands such as "engage the other one" or "protect me," you will carve out a little more flying room for yourself and shouldn't see quite as many inbound missiles with your name on them.
AI Wingman
Conversely, when designing missions from the Quick Mission Editor or the separate Mission Builder utility, you should have your multiship flights start in the air. The AI wingman pilots are highly prone to crashing into one another on the taxiways when you start them on the ground.
Codes
Code - Result
[SHIFT] + D - Cheat Message On
[SHIFT] + F (Repeatedly) - Refuel Internal Tank
[SHIFT] + S - Safe Mode On
Reach Speed 2,000 Knots+
To reach high speeds in excess of 2,000 knots, even to 3,000+ choose any plane, preferrably not a F-117A or A-10A, and go to about 30,000 feet. Then start rolling to the side by pressing and hold the directional key, or using your joystick by holding it to the right or left, to the side on full afterburner, as you keep spinning your nose should start pointing downwards, keep spinning and your speed can reach into the thousands. Sometimes the display stops at 998 Knots, but you are going faster anyway. This may make you plane shake but it can still be maneuvered. Going to very high altitudes through this method can cause your plane to go into a flat spin, which you won't be able to get out of. To speed up the whole process, press "C" to times to increase speed to 4X.