The 18-year-old -- who suffers from a form of epilepsy -- appeared in good spirits while dancers moved his wheelchair around to ABBA's track "I Have a Dream."
The insider reportedly did not want the pop superstar to be "dragged into this any further and he voluntarily gave up this information as part of a deal."
"The flight attendant called officials because I smoked a cigarette !!! And embarrass me which jeez I thought was kinda much," the pop star wrote via Instagram.