Hydra
The Hydra is the first jet fighter to appear in any GTA game, and is based off the McDonnell Douglas (now Boeing)/BAe Harrier II, although the air intake resembles that of a Lockheed F-16. The Hydra also includes an auto repair system which can repair the main body of the craft after minor impact. However it can not repair the wings or a head on crash. It is equipped with lock on missiles and flares as countermeasures. It's the fastest aircraft in all of San Andreas and one of the easiest to fly. You can switch between hover and flight mode by pushing the right analog stick forward/back. The Hydra can be attained by a cheat code or at "Easter bay naval station" at "Verdant Meadows" air strip after "Vertical bird", at Sweets house after 100% completion and at "Area 69" after "Black Project".
Enemy Hydras will deploy missles at the aircraft if the player attempts to get in. Two Hydras will go after the player at 4 star Wanted Level or higher and try to take down the player. The enemy Hydras should be no match, as they have a penchant for flying in lazy circles and not deploying flares.
Easter Eggs
Look at the side of the craft, behind the wings. You can see text DMA and something. DMA used to be Rockstar North.