How do you unlock the hydra jet fighter plane?

I'm sorry to say that you have to complete the mission vertical bird, for cj (its one of the last missions)

mivdyr

Yeah you need to do the mission. It's very later on in the game.

Or you can storm area 69 and find 1 inside with tanks,patriots and other rides

Vertical bird is the mission, in the start of the return to Los Santos chapter. Then it will be in a hanger in the desert airstrip.

After you come back to los santos for the final missions there is a mission where you must steal a hydra jet, after you complete that mission there will be a hydra jet at your personal airport.

You got to sneak into a amy ship and steal the plane in a mission.

Yes, it is called vertical bird. After that it will appear at your abandoned airstrip that you bought.

Get all the gold medals in the pilot school.

Yes. Once you complete the mission Vertical Bird, the plane will start appearing in a hangar to the side of your abandoned air strip - The one west of Las Venturas.

There is an easier way to get the Hydra.First,you have to unlock the 3rd island of course. Then on the third island you have to buy the abandoned airstrip.After that you have to unlock the races at the airport in San Fierro(before you do the next step,make sure you have only 3 vehicles in the hanger at the abandoned airstrip.After that go to the airport and go to the races.select Military Service and they will let you use a hydra.You will spawn at the abandoned airstrip to start the event.Once you're there,drive your hydra into the hanger at the abondoned airstrip.get out and it will say to get back in your vehicle and you will have 24 seconds.wait until the 24 seconds end and it will send you back to the airport in San Fierro.after that, fly or drive back to the abandoned airstrip and go into your hangar.the hydra will be there.