If you've been hired and disclosed in the interview, Spirit already decided that your bust could be overlooked. The background check is FBI stuff ('I omitted a stint in jail' type of thing), not FAA busts. Have you flown down to FLL to do the background check and ID photo visit? If so, just tell them then. If not, send an e-mail, better safe than sorry.

As for the 'cut and paste' story - I'd leave that out. Spirit is the airline that you've always wanted to work for, so why would you have apps in at other places?

I'm NOT in HR, just regular line scum. Welcome aboard!