A collision between two Ryanair jets sheared off the wing tip of one plane, with terrified passengers hearing a "loud crash".
The passengers were evacuated from both planes, although no one was injured.
Ryanair issued a statement saying that the wing tip of one plane and the tail cone of another "made contact".
The incident occurred when a Warsaw-bound plane and a jet from Frankfurt Hahn that had just landed smashed into each other in the parking area of Stansted Airport early on Saturday morning.
Essex police carried out breathalyser tests on both pilots, which gave zero readings.
Ren Ivaldi, who was on the Warsaw-bound flight, said on Twitter: "Huge loud crashing noise and totally felt the crush sitting at the back.
"Thank God it only hit the wing as if it was the body of the plane it'd been apocalypse... The other plane's wing is half crushed. No electricity on plane. No toilets, no ventilation."
— Ren (@imhoturenot) June 28, 2014
Ryanair spokesman Robin Kiely told the Daily Mail: "This morning at London Stansted the wing tip and tail cone of two Ryanair aircraft made contact while one aircraft was taxiing to stand and the other was commencing pushback from stand.
"Customers were disembarked and boarded two replacement aircraft which departed Stansted with a delay of approximately three hours.
"Our Stansted-based engineering team are currently investigating and will repair both aircraft and return them to service as soon as possible."
Passengers then faced delays of up to three hours.