Yeah, that's where you gotta save 'em. Funny story about it though:
I took hours getting the fucking plan past the tanks and jets while playing as Franklin. I finally do, and I get back to the airport and remember that I only bought a hangar on Michael. So I spend the next few hours trying to land in the airport and get rid of the 3 stars you get from landing there without owning the airport, which is a bitch because I had to stay near the plane so it didn't despawn.
I finally manage to, so I buy the hangar park the Titan, and run to find a car to try to park in its cargo hold. I get one and return, only to find two things:
1- There's a glitch that causes the Titan to explode whenever you return to it in the hangar.
2- The cargo hold, which doesn't open unless you punch it and drive a few feet, can't even fit a car without jamming it between the benches. And on too of that, unless you back into something small to close the cargo hold's door, the car will fall out. However, if you DO close the door, the car will flop around, take too much damage, and explode mid-air.
And we all know what that means.
So, yeah. At this point, the Titan is worthless in single player. You get your ass my crew and I will find a way to make use out of it when doing heists and deathmatches on GTA Online, though.