You need firered or leafgreen to trade you one.
You don't, you have to trade Aerodactyl from FRLG
The only way to obtain Aerodactyl in Ruby, Sapphire, or Emerald is to trade it from another game.
Aerodactyl does not evolve lolk?
Aerodactyl does not evolve.
My Pokemon party is Charizard, Lapras, Dragonite, Aerodactyl, Snorlax, and Kingdra for the Leafgreen version. =)