The Boeing 787, flying from the Washington, D.C., area to Munich, had to make a hasty return to the airport "to address a mechanical issue," United said.

A United Airlines flight traveling from Washington Dulles International Airport made an emergency landing last month after the pilot declared a mayday call shortly after takeoff due to engine failure.

A United Airlines flight bound for Germany declared "mayday, mayday, mayday" with an engine failure last month, forcing the jet to hastily retreat to Washington, D.C., tower recordings and the carrier said.