Trump gripped the railing of Air Force One as he took special care to walk down the steps after landing in Busan, South Korea, on Wednesday. The president is in South Korea for APEC meetings, as part of a global jaunt that has included visits to Malaysia and Japan.

The president fueled concern for his health after he cautious descended Air Force One's stairs after admitting he'll probably fall 'one day.'

President Donald Trump on Thursday joked aboard a trembling Air Force One how the bad turbulence would be interpreted. (Watch the video below.) In an interview with reporters on the flight home from his Asia trip, Trump noted the rough conditions as he steadied himself in a doorway.

Before the gleaming 747s that now ferry U.S. presidents across oceans, there was a smaller, sleeker jet that carried the weight of the free world.