A flight from Ljubljana, Slovenia, to London had to make an unexpected stop in Germany and passengers evacuated after a suspicious conversation was overheard on board.
A backpack belonging to one of the men was seized and later destroyed in a controlled explosion police said, according to Reuters.
The captain of flight EZY3246 chose to make an immediate diversion to Cologne-Bonn airport in Germany, and passengers were evacuated down emergency slides. A police spokesman confirmed that no unsafe contents were found.
Passengers evacuated the plane on emergency slides and police were waiting on the ground, the police spokesperson said.
The three men were handed over to police who questioned them "on suspicion they planned a serious crime against the state", the term used for terrorist attacks.
At around 10pm, the easyJet operations centre told passengers: "We're very sorry that your flight has now been delayed overnight".
He said there was no panic on board and everyone was briefly questioned by police and told they would be put up in a hotel.
"During the flight, other passengers had made the crew aware of the men".
"Early Saturday evening (10 June), a traffic machine flying from London to Ljubljana in London was exceptionally intercepted".
However, the passenger said it was 3am on Sunday before they were finally provided with a room.
The passengers had to "undergo a check immediately" and additional security checks were carried out on the plane.
Bild newspaper quoted a spokesman for the German federal police as saying the pilot chose to land the aircraft in Cologne after passengers told airline personnel they had heard the men using words including "bomb" and "explosive".
"The safety of easyJet's passengers and crew is our highest priority", it said.