Problem 1: You're comparing the fleet to a plane trip. The fleet was designed as a generational fleet, as a home. It's stated fairly frequently that it's a closed system, designed to travel near-indefinitely. Obviously attacks caused lost materials, but it was designed to travel for a while. As far as I can tell, it's been in space at least as long as Alto was alive, so that's at least 17 years. Can you imagine being in an airplane for 17 years?
Problem 2: Still seeing Zentraedi as giant humans. They have a right to be as they are. I don't see your problem, considering parts of the fleet were designed with that in mind.
