Will be unlocked through story anyway since you need to finish the flight school.
If you wish to complete it earlier
- Advanced driving school, down the street from your garage in SF. unlocked after Deconstruction (3rd mission after going to SF), Jethro will call you to tell you about the school.
Will be required to complete to unlock the purchase of Wang Cars later on and export lists that are required in another achievement.
- Boating school. Not related to anything. Bayside marina, above SF. Unlocked after Ya Ka Boom Kang
- Biking school, below the Venturas stadium in the west. Not related. Unlocked after completing Ya Ka Boom Kang.