I'm aware of that, but it's still unlikely it would need to weigh what an actual airplane weighs, much less actually weigh more (which was the original stated point). Even light fighter jets weigh around 10,000 pounds without any fuel, armaments, etc. -- if the cockpit of this spaceship was 2,000 pounds, and each of the fins was 1,000 (I can't envision them weighing that much, but for argument's sake), that still just puts it on par with the lightest fighter jets. It's hard to imagine it weighing more than that.