You would flip it to alt mode, even though it’s not flipping “back.”
Question about Unconventional Flying Object. Can this be played on a Spaceship that is already in bot mode in order to flip it to alt mode, essentially ignoring the first sentence as "already done" (somewhat similar to
Hunker Down)?
[Source: WotC]
No, it cannot.
Can a card target something even if it won't have an effect? For example, can Unconventional Flying Object target a Body mode character?
[Source: WotC]
Cards try to do as much as they can. You can play Unconventional Flying Object even if you don't have a Spaceship and it will only accomplish putting the Action into your scrap. There are a handful of Upgrades like
Crushing Treads that are restricted to play on say "Put only on a Tank." – you can't play that card unless you have the specific kind of character to put it on. After you successfully put it on the right kind of character, the game won't check anymore if the upgrade is valid, so the character can flip to Bot mode, stop being a Tank, and the Upgrade will stay on.