The car school has to be unlocked and is in san fierro. The plane school is on an airstrip in the desert you buy later in the game. The boat school is the far left-top corner of the map. and the bike school is in las venturas.
how far into it till it unlocks that. im doing the gang wars right now.
If I remember correctly, the gang wars is one of the last things you do in Los Santos. Then you have to play through some missions in a podunk town then San Fierro and it will unlock it. You are still a ways off from it.