CHICAGO (CBS) — A United Airlines flight was forced to return to O’Hare International Airport shortly after takeoff Thursday morning, after an engine caught fire. Authorities say a bird strike caused the problem.

The city’s Aviation Department said the pilot on United Flight 1738 to Miami, which took off around 7:45 a.m., reported an engine issue after takeoff, and returned to O’Hare around 8:30 a.m.

A passenger tweeted a video of flames shooting from one of the engines in mid-air.

Marco Vargas, who was driving past O’Hare in nearby Elmhurst, told WBBM Newsradio he saw flames shooting out of the plane’s right engine.

“I was just driving, and I couldn’t focus my vision on it, so I couldn’t identify it. It was a long flame shooting out of the right engine,” he said. “I called 911. They told me that somebody else had made that report, too, so I’m not the only one who saw it. When I arrived where I’m working, other people told me ‘Did you see that plane?’ Yeah, I saw it.”

United Airlines said the pilot shut down an engine on the plane after reporting a bird strike.

Once back at O’Hare, passengers were put on a different plane and eventually made it to Miami.

United says they will be reaching out to those customers on-board and offering to compensate them.

In the last five years alone, between O’Hare and Midway airports, the FAA reports nearly 1,500 bird strikes.