Police were called to an aeroplane at Birmingham Airport after a "civil dispute" broke out between passengers and an airline, a force has said.
A West Midlands Police spokesman said officers boarded the aircraft to stop the situation "getting out of hand".
According to the BBC, a chartered Viking Hellas flight was scheduled to leave Manchester for Athens at 1pm on Friday, but passengers were instead taken by bus to Birmingham. After they boarded a flight due to leave at 5pm they were told to get off, but refused to do so, it was reported.
They are said to have agreed to leave at 1.30am, before getting on a bus to return to Manchester.
A police spokesman said: "It was just a civil dispute and the police were there monitoring the situation to make sure it didn't get out of hand."
He said there had been "an issue between the airline and the passengers".
Speaking from the aircraft, a passenger named Dorota told the BBC the flight had been chartered and passengers were originally due to fly last Friday.
She said: "People are hungry. They have not eaten since this morning. The air conditioning has been switched off and it is getting hot. The airline will not give us food, only water."
She later said the group left the plane because there was "no point staying on".
The passengers had received a letter from Viking Hellas and were told they would be given a refund, she added. No one from Viking Hellas or Birmingham Airport was available for comment.