Step 1.Get to los santos airoport and jumb thru wall.
Step 2.Steal either the Dodo or the Jet.
Step 3.Fly in circles over the Los Santos Island.
If you enter the air space of the other islands (before they are opened) you will be shot down.
Estimated flying time
Dodo: 30 minutes.
Jet : 12 minutes
You can if you want to Wait and enter the San Fierro field and fly the Maverick chopper.Takes an hour approx.
If you are Good at control then fly out to sea for the time you will Glitch the game. If you succeed you may get a pilot license. Now,you can access all the airport and you skills will improve.
Still need to complete “Learning to Fly” School later in the game. There is no way around it. After getting the Official License from the School you can fly any of the planes at the Airports. At 30% flying skill a parachute is automatically added, while flying, too.Jump onto the Flight school seems to offer +60 for each bronze medal.Flying school adds 6% for each test passed, you need 18% for the license (gates at airports open) and 40% for the complimentary parachute. Flying distance adds skill in 5% chunks, and I'm pretty sure it's 50.000 ft for 5%. However there appears to be some deductions(?) so not all distance in the stats count for skill.Flying the Vortex adds driving skill, not flying skill.In planes, every 10 minutes of air time is 1% towards your flying skill.