Scumbag ex-Team USA doctor Larry Nassar got the private jet treatment Friday to fly from Michigan to Tucson to begin his federal prison stint ... and TMZ Sports has the photos.

Nassar boarded the plane at Detroit Metro Wayne County Airport in freezing Michigan temperatures -- the fact he didn't get a jacket makes us smile.

Records show the flight lasted 4 hours and 36 minutes. Nassar appears to be shackled and surrounded by law enforcement officials ... so we're guessing it wasn't exactly a Paris Hilton style private jet flight.

We asked the Federal Bureau of Prisons if it's typical for a high-profile prisoner to fly private but only got this response: "Due to security reasons, we do not share information on methods of prisoner transportation."

The good news ... Nassar has begun his 60-year sentence for child pornography crimes in a high-security federal prison in Tucson -- with roughly 1,500 other inmates.