A person without a valid ticket boarded a Norwegian plane en route from Oslo to Malaga on Thursday evening, writes Norwegian. TV2. 

The cabin crew only discovered it when another passenger turned out to have the same seat. 

But it wasn't a planker, it was a misunderstanding. 

– The ticket was mistakenly booked for the following day. The passenger was not aware of this, and upon boarding the person scanned their own boarding pass. The system gave an error message because the boarding pass was for a different departure, but this was unfortunately misinterpreted at the gate, says Norwegian's press manager Catharina Solli to TV2.

The person was allowed to get off the plane.

Source: Aftonbladet.se