You actually did say Jetfire parts at first. And the parts in the SB spot don't look like jetfire parts, so they really aren't "jetfire looking" either.

 

Here's a crazy guess.....

The jetpack thing we see int he trailer is the first type of power-up (dunno where it comes from - dont care whter its jetfires or not to be honest).

Then the second one could be the one from the toy that bay and that chick is holding with the weird trailer bits sticking out in an 'X' shape, which he uses to go into space!!!!!! (and that would also explain the reason that shot is outside NASA too!)

who knows ey?

 

I doubt optimus could keep reusing Jetfires corpse suit even if he wanted to. Jolt used what looked like high levels of magnetic energy into the two robots. Optimus would need Jolt to follow him around and remagnitize the jetfire parts and with Bay wasting Jolt I don't see the possibility of it.

 

I can't see Optimus Prime needing anyone's help getting to the Moon.