A US Airways plane from Philadelphia to Houston with 55 people was diverted on Monday, after a bomb scare triggered by a 'threatening note' on board prompted extensive searches.

The flight, which was diverted to the city of Bristol, landed 'without incident' at the Tri Cities Airport at Tennessee.

"It's a Philadelphia to Houston flight that was diverted to TRI, which is Tri Cities Airport in Tennessee, due to a threatening note. The flight has now landed without incident," a spokesman for the Transportation Security Administration said.

The passengers were questioned by the Federal Bureau of Investigation upon leaving the aircraft.

According to US Airways, its flight 3441 operated by Republic Airways, landed shortly after taking off at 10:10 am.

"There was a potential threat of a bomb," a spokeswoman for US Airways said.

There were 52 passengers and three crew members on the plane.

The incident involving the US Airways is the latest in a series that have been taking place in the country in the aftermath of the busting of the London [Images] terror plot that involved blowing up of air liners over the Atlantic. Security has been tightened up considerably at airports since then.