Queues, cancellations and delays dogged air travellers again today with passengers' dream holidays turning to nightmares.
But airlines were able to run far more services than on the previous day as airports and passengers learnt to cope with the demands of the new anti-terror regime.
Transport Secretary Douglas Alexander said the aim now was to match the scale of security needed to cope with the latest threat to the needs of busy airports.
He gave "heartfelt thanks" for the patience shown by passengers, some of whom told harrowing tales today of long waits at airports for non-existent services.
British Airways, which had to cancel more than 400 flights on Thursday, managed to reduce today's cancellations to just over 100.
Having only run about 10% of its short-haul flights in and out of Heathrow on Thursday, BA was able to operate around 70% of its short-haul programme from the west London airport today.
Budget airline easyJet axed 112 flights today but tried to limit cancellations to destinations which passengers could take trains to. Rival low-fare carrier Ryanair had to scrap more than 50 flights.
Some of the worst travel chaos was endured by passengers due to fly to the USA.
BA cancelled six American flights from Heathrow, including three to New York, and there were long waits for transatlantic services for passengers flying from Manchester airport.
One of the unluckiest travellers was Leicester University student Michael Collins, 20, who was attempting to attend his parents' wedding anniversary in France.
Having had his flight from Nottingham cancelled on Thursday, Mr Collins rebooked from Stansted today only to find - having journeyed from his home in Sheffield - that this second flight had also been axed.
He said today: "It seems I've spent the last day or so sitting in airports or trying to get trains to another airport.
"Now there isn't a flight to Nantes until next Monday, so it looks like I won't be going to France. I'm heading back to Sheffield."
Carl and Vanessa Edwardson, from Crosby, Merseyside, had hoped to fly to Canada from Manchester at 11am today but were told they were likely to be stranded in the UK until 4am on Saturday.
Electrical engineer Mr Edwardson, 39, said: "We were looking forward to the holiday of a lifetime and we hope it is not the nightmare of a lifetime."
Some people, including Isabel Middlemiss, 72, slept overnight at an airport only to find that there was no hope of getting a flight to their destination.
Mrs Middlemiss, from Hounslow, Middlesex, who had intended to travel from Gatwick to Egypt with her sister, said: "Although I'm very sad not to be going on holiday, we have got to appreciate the situation."
The palm for persistence could well go to Frenchman Fernando Viegas, 63, who spent Thursday night at Gatwick waiting for a flight to Portugal and was preparing for another night at the West Sussex airport in the hope of getting away early on Saturday morning.
"I'm very tired, but what can you do?" he said.
Airlines and airports said passengers had generally responded well to requests not to arrive with hand luggage. But despite the warnings, some passengers were observed at Heathrow hastily repacking their bags to meet the new requirements.
A Heathrow airport spokeswoman said tonight: "Things have been a lot better today than on Thursday.
"There will be delays again tomorrow (Saturday) but we are expecting and hoping that there will be another big improvement in punctuality."