There are a couple of scenes in the movie that they do:
- During Starscream's coronation, the Constructicons are playing trumpets/bugles.
- During the Hot Rod/Galvatron battle inside Unicron, Galvatron attempts to strangle Hot Rod
You don't really need oxygen to blow trumpets. Just gas.
Seize the moment, 'cause tomorrow you might be dead.
I don't think they breathe oxygen. Remember the departed Decepticons were floating in space until they meet Unicron.
The strangulation from Galvatron isn't cutting off his oxygen, just preventing the gasses, fluids, internal circutry to not work. Like cutting a gas line in your car it will stop it from functioning.
----------------------------------------
Is this Idaho? Because I will not limbo in Idaho.
I'm pretty confident they don't breathe oxygen
shareThere was also a scene where they were underwater on the quintesson planet.
So no. But they can probably manipulate air particles...you know, so they can play trumpets.