I wouldn't really attribute it to sheer luck. The Aurora class and Agrius class sized Garlean ships have the ability to remain aloft and motionless. At that point it's just a matter of finding a cloud big enough, and they're in a region of the world called, "The Sea of Clouds."

You can actually see, what I assume is an Aurora class, remaining immobile and airborne in the Ghimlyt Dark dungeon if you look up on the way to the first boss.