Britain named 19 people on Friday suspected of an Islamist plot to blow up transatlantic airliners and ordered their assets frozen, as governments scrambled to respond to a threat officials said could have matched September 11.
British police were believed to be questioning 24 people they arrested early on Thursday in raids US officials said had foiled by a matter of days simultaneous attacks on up to 10 aircraft flying from Britain to the United States.
Tough air travel security measures imposed immediately after the arrests continued in force on Friday although the chaos that struck airports on Thursday, when hundreds of flights were canceled, diminished somewhat.
There were still long queues at British and US airports, and security analysts predicted restrictions, particularly on hand baggage, could stay in place for months or years.
"I think we are both going to kiss the ground when we touch it in Los Angeles," said Mandy Macdonald, a US resident waiting to catch a plane from London's Heathrow airport.
Police said the plan was to blow up planes with chemical bombs smuggled on board disguised as drinks. The US Homeland Security Department said the 24 people arrested in raids between Wednesday night and Thursday were British Muslims.
The Bank of England, acting on instructions from the government, published the names and home towns of 19 suspects, saying it would be illegal to release their funds. It was not immediately clear why it had not named the five others arrested.
Those being held are aged from 17 to 35 and live in east London, the town of High Wycombe, west of the capital, and Britain's second city of Birmingham.