The skeleton for this needs to be light so it can fly?
Options:
- building
- aircraft
- ship
- closet
- closet
Let's think carefully first. Step-by-step reasoning process:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
It is the aircraft that can fly. The skeleton for an aircraft needs to be light so it can fly. So the final answer is aircraft.