Find enemy units in stealth mode:
Take a scout or truck near a rocket launceh or tank. Move it around the
screen until you find the unit. Then, take it out with the rocket launcher
While playing the game save, then open up the menu and choose the
"Surrender" option and the general will tell you a new strategy.
After that, reload or restart your game.
To finish the Air Tutorial, try to keep all AA guns alive. Use helicopters
against the general's air. Then, use AA if air cannot reach the generals.
Use AA to also kill infantry quickly.