Passengers shed tears of frustration and worried aloud about flight safety while waiting in long, chaotic lines at Britain's airports Thursday, after the announcement of an alleged terrorist plot brought air travel to a halt.
At Heathrow, Britain's busiest airport, check-in lines stretched out the door, armed police patrolled the terminals and staff struggled to keep up with a flood of questions from travelers at the height of the summer travel season.
Some passengers stood for hours in slow-moving lines, while others gave up and sat, surrounded by piles of luggage.
Kendra Webb, an 18-year-old student from San Francisco, cried as she spoke on the phone to relatives back home.
"This is hell," she said. "I hate this airport. I just want a cigarette right now."
Police said they had disrupted a plot to simultaneously blow up several aircraft between Britain and the United States using explosives smuggled in hand luggage
The British Airports Authority, which runs several major airports, told passengers to expect long delays and stringent security measures. Passengers were told to check all baggage. Only plastic bags carrying passports, money and other essential items were allowed onboard.
British Airways scrapped more than 200 domestic and European flights. Heathrow - which normally sees 1,250 departures and arrivals a day - was closed to arriving European flights, and airlines including Alitalia, Lufthansa, Iberia and Aer Lingus canceled flights to Heathrow.
Some flights were leaving, but with severe delays.
"It's scary," said Fran Barkan, a teacher from Long Island, N.Y., trying to fly home. "The whole flight will be worrying. It's not going to be a comfortable flight - if we get on today."
Many flights out of London's Stansted Airport were also canceled, and most of those that went were delayed, some by several hours.
There was a heavy police presence inside the crowded terminal and a police helicopter circled overhead.
Passengers stood in long lines for security checks, clutching transparent plastic bags containing the few items they were allowed to take on board. Mothers of bottle-fed children were required to taste the contents of bottles in front of security staff before being allowed to take flights.
"It's absolute chaos," said Vanessa Lee, who traveled two hours from Spalding in eastern England to fly to visit friends in Pisa, Italy, but found her flight canceled. "Ryanair's computers keep crashing because they can't keep track of all the changes."
Associated Press Writer Sue Leeman contributed to this report.