There were awkward scenes after a man and woman awkwardly emerged from a plane toilet together in front of fellow passengers queuing to use the loo.
The passengers were accused of joining the mile high club after spending about 10 minutes inside the locked lavatory.
Professional beach volleyball player Stafford Slick shot video of the moment the man exited the loo and was quickly followed by a woman as others waited on board the United Airlines flight.
Mr Slick posted the video on Instagram, writing: "Couldn’t believe my eyes. I’ve heard the legends, but never thought I would see it in real life #milehigh."
Do you know the man and woman or were you on the flight? Email webnews@mirror.co.uk.
The video showing the man and woman - who were wearing red jumpers - has since gone viral.
It shows a queue of women waiting for about "ten minutes" outside the loo, according to a caption.
A flight attendant pushes a drinks trolley past them, saying to one of the women: "You're still right here?"
The passenger replies: "There's folks in there."
The lavatory door finally opens as the man - who has a black bag strapped around his upper body - comes out first, followed by the woman.
Passengers in the queue are seen smiling as Mr Slick, who is seated nearby, records the footage.
The 6ft 8ins volleyball player, who lives in Hermosa Beach, California, wrote on Instagram: "These women had been posted up on the lavatory, ready for a ballpark of 10 minutes."
He added: "I've been on a LOT of flights... this is a first."
The athlete, who competes in the FIVB World Tour, also joked: "Now I've seen everything"
Mirror Online has contacted Chicago-based United Airlines for comment.
It comes as Love Island 2019 star Amy Hart revealed some of the most shocking things that happened while working as a British Airways flight attendant.
On one flight, a husband and wife who joined the mile high club were congratulated by the entire crew as they emerged from the toilet, she said.
The captain got the pair a bottle of Champagne.
A former flight attendant recently told how crew know when a couple have had sex on a plane.
She said the lavatory door would "always shake" while the couple romped.
