Grand Theft Auto: San Andreas Message Board  

do i need to finish the school of how to fly and mission of zero

You have to finish the Flying School if you want to continue the campaign. If you don't do it you can't continue doing the missions where you have to fly a plane.

If you want to get 100% you have to do Zero's mission and I think you can't unlock the Wang Car's asset unless you do Zero's missions first.

YOU HAVE TO FINISH THE FLYING SCHOOL.BUT IT IS NOT IMPORTANT TO FINISH ZEROS MISSIONS.FINISHING THE CAR DRIVING SCHOOL ALLOWS US TO BUY WANG CARS SHOWROOM AND SHOWROOM ASSETS

Then You Can finish the game too!