Bomat Bazaar Barge

For a Vehicle to be able to attack, it must be a creature as the declare attackers step begins, so the latest you can activate its crew ability to attack with it is during the beginning of combat step. For a Vehicle to be able to block, it must be a creature as the declare blockers step begins, so the latest you can activate its crew ability to block with it is during the declare attackers step. In either case, players may take actions after the crew ability resolves but before the Vehicle has been declared as an attacking or blocking creature.

You may tap more creatures than necessary to activate a crew ability.

If a permanent becomes a copy of a Vehicle, the copy won't be a creature, even if the Vehicle it's copying has become an artifact creature.