GTA 5 Xb1 query

[dfen5]

Just played a mission on line, can't remember the name; you have to get into fort Zancudo, steal the jet and shoot down a brief.
Trouble is, you can get out the jet easy but I was stuck in a car in the base, couldn't find a way out? Rest of the team finished the mission but all I could do was drive around the base getting shot.
Can you get a car out the base by a ramp or something? There was only one jet and two of us broke in...

[ZedLeg]

If you hit the ramp at the east end of the runway at an angle towards the fence you'll end up on the dirt road by the river. There are probably other ways but that's how I do it.