Stringent security measures remained in place at UK airports last night after a day of chaos at transport hubs across the country.
At Heathrow, the worst-affected airport, the congestion eased yesterday evening after some short-haul flights - including Aer Lingus services to Dublin, Cork and Shannon - resumed and travellers stranded by cancellations heeded the advice of airport authorities and left for the night.
Throughout the day heavily armed police with sniffer dogs patrolled the airport's terminals and passengers were subjected to a range of extra security procedures, including a ban on hand luggage and restrictions on liquids.
Heathrow's Terminal 1 heaved with passengers through the afternoon. By 5pm, the longest queue fanned out in a loose ark from the Aer Lingus check-in desks, where hundreds of passengers stood in the hope of finding a seat on a late flight to Ireland. The queue stretched almost the length of the departure floor, blocking doors and passage-ways for hundreds of metres.
Near its head was Denise O'Connor from Cork, who was travelling home with her four young children. They had arrived at Heathrow in time for an early-morning connection from New York and now they were still not sure if they would make it home.
"This is our fourth queue today, and every one takes two hours. It's crazy. I've four children on my own, and no one has told us anything.
"I think what's happened is terrible, but there's definitely not enough contingency plans. My children have been up for over 24 hours - we left our place in New York at 3pm on Wednesday and now it's 5pm on Thursday and we're still not on a plane."
Ms O'Connor said all passengers whose connecting flights were cancelled had earlier been advised by airport officials to "go home".
"They were telling people to go home, but how do I go home? One man working here said he had never seen anything like it . . . We're cranky."
Behind her, many of those standing were unsure if they would make it home before morning. James Leonard's flight to Shannon, where he lives, had been cancelled, but now he waited for any flight that would bring him to Ireland.
"We got in and they told us there was no flight to Shannon, so now we're hoping to get to Dublin. All we're being told is to stay in this queue."
At the other end of the terminal, at check-in zone F, a middle-aged couple lay sleeping on an improvised bed of suitcases and swivel chairs, oblivious to the children crawling around them and the weary voice of the public
announcer.
At the security gate, passengers were told they could carry no hand luggage on board and were issued with leaflets telling them that only travel documents and essential items could be brought into the cabin. These were to be placed in special transparent plastic bags being handed out by airport staff.
Nearby, the bins brimmed with discarded bottled water, spectacle cases and toiletries. One woman debated whether to bin her expensive-looking handbag to save having to queue for two hours to have it checked in.
Back at the Aer Lingus queue, Gerry O'Sullivan and his wife were nursing their sick eight-year-old son, who lay his pale face on the base of a luggage trolley near the doorway.
The family of four were en route to Cork from Australia, but by now they had all but given up on reaching home tonight. Now, anywhere would do.
"One of the kids is sick and I told them that, but it did no good. They just said 'queue up and you might get on'. I think there should be more people here. There should be more representatives from the airlines. We just don't know, that's what's so frustrating."
With information hard to come by, scores of people loitered in the cramped newsagents, where stocks of London's Evening Standard were running low. So intense, so all-consuming was the bedlam on the terminal floor outside that its lead headline - "Mass murder terror plot" - managed to feel somehow remote.