President Barack Obama is switching planes in Philadelphia for his return trip to Washington because of a mechanical problem with a flap in his earlier aircraft, the White House says.

The White House described the problem as minor.

Obama on Sunday traveled to Connecticut and Pennsylvania to campaign for Democrats in gubernatorial races.

He had flown on a US government C-32 plane, smaller than the 747 jet he typically flies in.  Any aircraft the president is used is identified as Air Force One. After discovering the mechanical problem, Obama and other travelers with him switched to a backup C-32.