Article continues below advertisementDonald Trump left people scratching their heads after a strange comment during his return trip to the U.S. from the United Kingdom.While boarding Air Force One, the former president gave reporters a polite send-off.Article continues below advertisement"Thank you, everybody. Have a good flight," Trump told the press in a clip. "Fly safely."He added, "You know why I say that? Because I'm on the flight, otherwise I won't care.