A passenger has allegedly had half his ear bitten off in an attack on a plane from Newcastle bound for Ibiza.
The incident took place on a Jet2 flight to the holiday island just before it was due to land.
The man has reportedly being receiving treatment in Spain since the attack, which happened on Sunday evening.
One passenger told the Daily Mirror: “It was absolutely sickening and I find it unbelievable that anyone would do that at all to another human being.”
The airline said it was investigating the incident and the safety of passengers was of the utmost importance.
Jet2.com managing director Phil Ward said: “We are working closely with Northumbria Police and the parties involved to fully investigate the reported incident so that we can take the appropriate action.
“The safety of our customers is of utmost importance to us and aggressive behaviour will simply not be tolerated.”
A Northumbria Police spokesman said: “We’ve received a report of an assault on an aeroplane in Ibiza on Sunday evening. Inquires are ongoing into the incident.”