Last month, an Airbus A321 took off from London Stansted Airport, missing two windows. The issue wasn't noticed until the plane reached an altitude of 15,000 feet.
There were 11 crew members and nine passengers on the flight.
A report released by the United Kingdom's Air Accidents Investigation Branch said the flight took off on October 4, heading to Orlando, Florida.
About 10 minutes after takeoff, the loadmaster walked toward the back of the plane and discovered that one of the windows was damaged.
"He noticed the increased cabin noise as he approached the overwing exits, and his attention was drawn to a cabin window on the left side of the aircraft. He observed that the window seal was flapping in the airflow, and the windowpane appeared to have slipped down. He described the cabin noise as 'loud enough to damage your hearing,'" the AAIB report states.
While the damaged window didn't appear to be causing any issues with the flight, the pilot decided to turn around and return to Stansted Airport. The passengers all deplaned safely, and there were no reports of injuries.
Once the plane landed, technicians found that four windows were damaged.
The AAIB determined that a film shoot the day before caused the issues with the windows. Photos from the shoot showed multiple floodlights pointed at the windows.
"The windows appear to have sustained thermal damage and distortion because of elevated temperatures while illuminated for approximately four to five and a half hours during filming activity the day before the flight," the report says.
The AAIB noted that if the damage had been more severe, it could have caused serious issues as the flight climbed toward cruising altitude.