An Egyptair flight from Cairo to New York was redirected to the U.K. this morning after a passenger found a note in the plane's restroom that read "I'll set this plane on fire" and included a seat number.

The JFK-bound flight was instead escorted by British fighter jets to the Glasgow airport, where a technical team is currently investigating. 326 passengers were forced to wait on the plane for more than three hours, but the AP is reporting that they were eventually allowed to get off and wait inside the airport.

The BBC is reporting that a BBC producer discovered the note, which was written on a napkin with a pencil, in a restroom sink three hours into the flight. Flight attendants immediately locked the bathroom and contacted authorities.

Officials say that they will interview and investigate all the passengers before allowing them to resume their flight to New York.

And, in somewhat-related airport security news, this week a nine-year-old British girl was able to use a fake unicorn passport — with a large photo of a stuffed unicorn inside — to get through Turkish customs.

[BBC, image via Twitter]