Two passengers and their emotional support French bulldogs were removed from a Norwegian Air flight Thursday after the dogs showed signs of "distress". 

The Boeing 787 from London to Austin, Texas, was due to depart at 11 a.m. BST (6 a.m. EDT) but was delayed by an hour and a half due to the incident. The dogs were wearing tutus and were kept in holdalls on board the flight. They became anxious as the flight headed to the runway for departure from Gatwick Airport.

A spokesman for Norwegian Air said the captain of the flight decided to ground the "distressed" dogs and their owners at the gate after they failed to calm the pets.

Norwegian Air allows emotional support dogs on a direct flight for people with mental or emotional disabilities to and from the United States.

"The safety and security of our passengers and crew is always our number one priority," the spokesman said.

Emotional dogs are becoming very prevalent with fliers who suffer anxiety, nervousness, stress, high blood pressure, and other mental and physical issues during long-distance trips.

A spokesman for Gatwick Airport said the support dogs were fully verified and had met all necessities, including passports and paperwork, when passing through airport security and boarding.

In a similar incident, a flight attendant required five stitches after he was bitten on the hand by an emotional support dog in July. The incident occurred on board an American Airlines flight from Texas to North Carolina. According to People, the dog bit the flight attendant when he was trying to retrieve the sick bag from the passenger’s seatback. 

French Bulldog In this photo, a French bulldog is pictured during a demonstration against animal abuse and condemning dogfights, in Arona on the Spanish Canary island of Tenerife, March 12, 2017. Photo: DESIREE MARTIN/AFP/Getty Images