Shia LaBeouf -- I'm NOT Joining the Air Force!!

Don't panic, Shia LaBeouf is NOT joining the Air Force ... his recent visit to a recruiter's office was just prep work for a new role he's eyeing.

Our Shia sources tell us his trip to the USAF office in L.A. Saturday wasn't a whacky publicity stunt -- he's really trying to learn about the enlisting process -- from recruitment through basic training.

LaBeouf hasn't locked down the potential role yet ... he's just doing his homework.

Unfortunately for Shia, the office was closed. Damn budget cuts.