Sorry for the weird sound on this, I’m not sure what happened! Regardless, enjoy airborne tank!
Thats badass man! Laughed for a minute straight.
This happened because you were parked on top of one of the shields shown in the video beside the tail end of your tank. Once the shield regenerated, it pushed your tank into the air lol.
Thanks Jestzer for the clickable link - my bad on that one 
I do enjoy doing this