It’s not a good idea to board an international flight without a boarding pass or passport.

Passengers were forced off of a flight before it took off when it was discovered that an intruder had made his way onto the plane, according to media reports. The man then attempted to barricade himself in the plane’s bathroom.

Airbus A320 Vueling Airlines at Munich Airport ready for takeoff

Police reportedly received a tip that an unidentified individual had entered the plane illegally, prompting the airline to force the other passengers off the flight. (iStock)

The incident occurred on a Vueling flight from Barcelona to Dublin on Monday morning, Yahoo News reports. The plane was originally scheduled to take off at 12:40 p.m. local time but was delayed.

Police officials said they received a tip that an unidentified individual had entered the plane illegally. The intruder not only did not have a boarding pass but also did not have a passport, even though it was an international flight.

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Passengers were forced off the plane while authorities handled the situation.

According to the Barcelona Airport website, the flight eventually took off at 3:21 p.m. local time.

A social media user tweeted at the airline about the delay, prompting a response from Vueling. When asked about the status of the flight, the airline posted: “We are working in order to speed the process up. Our colleagues will inform you in the shortest time possible.”

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About an hour later, the airline posted, “We inform you that we are checking-in all the passengers again, and we will start boarding as soon as we can. We are doing our best in order to depart as soon as possible.”

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Vueling Airlines did not immediately respond to Fox News’ request for comment. It's unclear if the man faces charges.