A man has been overpowered by cabin crew on an Alitalia flight from Paris to Rome, after he drew out a small knife and demanded the plane divert to the Libyan capital, Tripoli.
A female flight attendant was slightly injured as the man was subdued.
The suspect, from Kazakhstan, was handed over to police and arrested after flight AZ329 landed at Rome's Fiumicino airport at 2005 GMT.
He was "clearly agitated", according to a statement from Alitalia.
There were 131 people on board.
The man was overpowered by four crew and passengers, and given a sedative by a doctor who was travelling on the flight.
Italian police named the man as Valery Tolmachev, aged 48. He is reportedly a member of the Kazakh delegation at Unesco in Paris.
Italian media say the man brandished a nail-clipper in the assault. He had no previous criminal record, nor any links with militants, the reports said.
The motive for the attack is not yet clear.
The incident, near the front of the plane, was over so quickly that passengers seated further back were unaware of it, Italy's La Repubblica newspaper reported.