'Threatening note' found on jetliner; flight diverted

A San Diego-bound passenger plane that departed Detroit Metro Airport on Sunday was diverted to New Mexico after a flight attendant found a "threatening note" in one of the passenger lavatories, authorities said.

A security sweep of Delta Flight 1706 turned up no threat, according to the Transportation Safety Administration.

The incident happened as airlines remain on heightened alert a week after a team of U.S. Navy SEALs killed al-Qaida leader Osama bin Laden.

Delta Air Lines said the flight, carrying 137 passengers and six crew members, was diverted "out of an abundance of caution."

On Christmas Day 2009, a passenger attempted to detonate an explosive in his undergarments on a Delta flight as it landed into Detroit Metro. The attempt was botched, and the flight from Amsterdam landed safely.

Umar Farouk Abdulmutallab, the so-called underwear bomber, awaits trial.

Also Sunday, a Continental Airlines flight from Houston to Chicago diverted to St. Louis after officials say a passenger tried to open a plane door during the flight.