Washington-bound passengers held over in Heathrow Airport (search) swallowed their disappointment and decided 'better safe than sorry' after British Airways canceled its afternoon flight from London for a second day over security fears.

"It's what they've got to do," said Josh Clark, 22, from Roanoke, Va., who was among the 300 passengers booked on the flight. "If it's a security matter then I would rather have them cancel it than go through with it. I'd rather be safe."

The airline called off Flight 223 to Dulles International (search) less than two hours before scheduled take-off Friday, and some passengers had already begun checking in.

The airline said a security warning from the British government prompted the cancellation. But neither airline nor British officials would give details on the security concerns, which also caused the cancellation of the same flight on Thursday

On Wednesday, Flight 223 was kept for several hours on the taxiway after landing at Dulles while authorities questioned passengers — because of intelligence information that raised concerns over individuals on the flight, according to a U.S. national security official. Investigators found no evidence of terrorism.

British Airways runs three flights a day from Heathrow to Dulles. Before the canceled flight, Flight 217 was delayed for two hours as U.S. security authorities requested further information from the airline, but it then took off. The third flight, British Airways 225, took off shortly after its scheduled time.

"I am irritated," said Deepa Menon, 28, a law student from Washington who was on the canceled flight. "I am sure there are reasons but I do wish we had known what was going on earlier."

But Mike Coppolelli, 39, a Washingtonian who lives in London, supported the airline's decision.

"We can't just sit around and wait for another catastrophe to happen and say, 'Oh gosh, we shouldn't have gone,"' he said. "I feel more comfortable knowing they've canceled it and something has possibly been averted."

More than a half-dozen flights to and from the United States have been canceled in the past 10 days, as authorities tightened security restrictions on U.S. airspace over the Christmas and New Year holidays.

Last month, the Bush administration raised the national terrorism alert to orange, its second-highest level, saying there was intelligence terrorists could be planning large-scale attacks over the holiday season.

In response to U.S. demands, last month the European Union agreed to share airline passenger lists for all U.S.-bound flights with American officials.

Britain's Home Secretary David Blunkett (search) spoke by telephone with U.S. Homeland Security Secretary Tom Ridge on Friday to discuss ways to minimize disruption on trans-Atlantic flights, the Home Office said.