How can I save a Rhino Tank in my hanger?

I want to steal (and not buy) a tank in GTA 5 Story Mode, and I want to keep it permanently.

I read here that tanks can be saved in my hangar. I've managed to steal one from the military base and drive it all the way to the hangar. I of course have a 5 star wanted level by the time I get there.

I've also managed to put the tank in the hangar and get away in the plane that was already there. However, when I came back to enjoy my new tank, it wasn't there.

My suspicion is that you can't save anything in the hangar if you have a wanted level. Is that the case?

Update

I realized I could drive to the sewer tunnel opening by the canal, one of the few places big enough to drive the tank in and successfully hide. I did this, and managed to get unwanted again, but when I put my tank in the hangar it didn't stay there. When I came back it was gone. Is it actually possible to save tanks in Story Mode?

hangar is for aircraft only... you need to purchase a garage for your cars.