Hundreds of thousands of people are thought to have been affected by flight cancellations and delays, caused by an air traffic control issue on Tuesday
Transport Secretary Heidi Alexander apologises "wholeheartedly to passengers" and asks the UK Civil Aviation Authority to conduct an independent review
In a statement, the regulator says people are "unlikely to be entitled to compensation for delays or cancellations that were directly caused by the incident"
Throughout the day, images have shown passengers sleeping on airport floors, with aviation analytics firm Cirium saying more than 340 flights were cancelled today - around 5% of the total
Newlyweds Sasha and James say "it feels like we will spend our honeymoon at Gatwick", while one woman due to leave Turkey on Tuesday is now stuck until Thursday
Has your flight been cancelled? Our correspondent takes you through your rights
We've got another update from aviation analytics company Cirium, which is tracking flight cancellations across UK airports.
It says 327 flights are cancelled or did not fly so far on Wednesday, including 140 departures and 187 arrivals.
Cirium says this works out as 5.57% of the 5,869 flights scheduled on Wednesday.
Image source, ReutersWe can now bring you more from Aviation analytics firm Cirium, who say 291 flights have been cancelled so far today.
Cirium reports that 120 flights due to depart from UK airports were cancelled on Wednesday. A further 171 flights due to arrive into UK airports were also cancelled.
Heathrow Airport - which has the highest proportion of scheduled flights - is experiencing the highest number of cancellations so far today, with 67 departures and 120 arrivals being cancelled.
At Edinburgh Airport nine departure flights were cancelled and three arrival flights were cancelled.
London Stansted Airport and Birmingham Airport are experiencing the lowest number of cancellations.
One departure flight was cancelled in each airport and a further arrival flight was cancelled at Stansted.
No arrival flights were cancelled at Birmingham Airport.
Andy Burnham's official spokesman says the government does have confidence in Nats boss Martin Rolfe.
Speaking to reporters on Wednesday, the spokesman says: “We have confidence in him and he’s been tasked with the investigation, which will report in a week’s time.”
Image source, AFP via Getty ImagesPassengers pictured queuing up to check into their flights at Gatwick Airport this morning
We've been hearing from passengers who have been caught up in the flight disruption across the country.
Here's what they had to say:
Mary Litchfield
Your Voice
Image source, Sasha GrahamSasha and James from south London were due to fly to Madeira for their honeymoon yesterday afternoon when their flight was cancelled.
After getting married at the weekend, the couple were boarding their flight to Funchal from Gatwick Airport when they say they were "turned right back around".
"We spent three hours stranded in Wetherspoons, making the best of it," says Sasha.
"It’s certainly not the experience we planned, but I think starting your marriage with a national disruption is certainly very memorable!"
The newly weds have managed to book onto a different flight leaving Gatwick Airport this afternoon, but they're currently without their luggage after leaving it at the airport last night.
"By the time we got to baggage reclaim, it was almost midnight, there were no staff, and no information on the screen, just bags everywhere.
"We had no chance of finding our bags, so we abandoned the idea to get the last train back to London."
Sasha says they hope they can retrieve the luggage in time for their flight, but "judging by the news, it's unlikely".
"It feels like we will spend our honeymoon at Gatwick," she adds.
As we've reported, British Airways has cancelled a further 198 flights today due to the knock-on effected of Tuesday's disruption.
Here is what other airlines have said:
Mary Litchfield
Your Voice
Image source, Paul WillowsPaul Willows, 52, is currently stuck in Rhodes with his family, including his 85-year-old aunt and uncle, after their flight to East Midlands airport was cancelled last night.
They eventually got dropped off via coach to a hotel at 05:30am where they tried to get some sleep in a conference room.
"They stripped all the cushions off the sunbeds and laid them in the conference room. I dare say there were about 80 of us on the floor," Paul tells the BBC.
Paul says some people "found settees to crash out on", adding: "It's not been a comfortable night at all."
Despite this, he says: "There has been a good element of pulling together."
Paul, who is due back at work tomorrow, is still waiting to find out when his flight home may be.
Yesterday's air traffic control failures have continued to have a knock-on impact on flights out of UK airports today.
Image source, Getty ImagesSeveral people have had to resort to lying on the floor as they wait for updates on their flight status
Image source, Getty ImagesWhile others are still queuing at the check-in desk
Image source, Getty ImagesTens of thousands of passengers were hit by disruption which saw more than 1,750 flights cancelled on Tuesday, according to aviation analytics firm Cirium
Image source, Getty ImagesNational Air Traffic Services (Nats) boss, Martin Rolfe has ruled out a cyber attack, saying teams are carrying out a "thorough" investigation
Aviation analytics firm Cirium says 291 flights have been cancelled in UK airports so far on Wednesday.
Of the 291 cancelled flights, 120 were departures and 171 were arrivals, Cirium tells the BBC in an update.
The company adds that this is around 5% of the 5,869 flights scheduled, and that a normal day sees cancellations of between 1-2% of flights.
In a new update, British Airways says 198 flights scheduled for Wednesday have so far been cancelled.
It has confirmed that 349 of its flights on Tuesday were cancelled due to the disruption. This is up from the 260 reported earlier.
Image source, Getty ImagesBritish Airways has announced the cancellation of 190 flights on Wednesday due to both crew and planes being "out of place" following yesterday's disruption.
It follows the cancellation of 260 of the airline's flights on Tuesday due to the widespread air traffic control issues.
BA says it worked "throughout the night" to build a new flight schedule for Wednesday, but says it was "left with no choice" but to cancel the further flights.
It adds that while the incident has been "completely outside of our control" it apologises to the "tens of thousands" of affected customers.
Angela Ferguson
BBC News North West
A family has told the BBC how they had to spend the night on an airport floor after their flight from Turkey to Manchester was cancelled.
Alan Jones and Kelly Fewery and their son and niece, from Blackpool, were caught up in delays at Dalaman Airport due to the air traffic control problem.
Jones says they were due to fly out from Dalaman Airport at 23:30 local time, adding: "We are all absolutely exhausted. We got very little sleep."
He says they did not have any blankets or pillows and there were other families around them who were struggling.
He says they have now been told a flight is on its way to help return passengers home.
Jet2 has been approached for comment.
Katy Austin
Transport correspondent
Image source, PA MediaAirlines’ international schedules are really complex.
Large-scale disruption means planes and crews get stuck in the wrong position.
For example, diverted to an airport they weren’t expecting to be at, or having a flight cancelled so they can’t get to where they were meant to be for their next service.
Aviation consultant John Strickland also points out some crew will have worked all the hours they legally can, and need rest. Again, that not may be in the location they were expecting to be.
It's also still the tail end of summer – September is still a relatively busy month. This means there isn't necessarily lots of free space on planes to get stranded passengers home quickly.
That's especially true for destinations with a lower frequencies of flights.
The extent of disruption will vary per airline, but some will struggle to get completely back to normal for days.
Image source, Getty ImagesSome disruption remains following Tuesday's air traffic control fault which saw tens of thousands of passengers impacted.
Some airports are reporting more disruption that others. Those that have provided updates on Wednesday morning include:
Travel expert Simon Calder says, by his workings, there are about 250,000 people "waking up where they did not intend to be this morning" due to Tuesday's travel chaos.
"It was just awful," Calder told BBC Breakfast earlier this morning.
"I'm afraid today is going to be horrible as well," he said.
A Heathrow spokesperson has since told the BBC flights are operating, but some "knock-on impacts" are expected.
Calder said the issue may be fixed, but pilots, planes and passengers are "out of position" and so many people will be "waiting until the weekend" before they get where they need to be.
Kevin Peachey
Cost of living correspondent
It looks like it could be another frustrating day for air passengers, and many will be unsure about their rights.
On one level, it's quite simple. If your flight is cancelled, your airline is still obliged to get you to your destination, even if it is on another carrier, or give you a refund.
For delays, you may have the right to food, or a hotel stay, depending on the length of the wait.
When delays and cancellations are the fault of an airline, then passengers may be entitled to extra compensation. But, clearly, air traffic control issues are beyond the control of airlines, so no extra payments will be made.
Experts are urging passengers to check the advice from your airport, tour operator, and airline apps on a regular basis.
Have you been affected by the disruption? Are you still stuck where you are? Share your experiences with us through the following ways:
Please read our terms & conditions and privacy policy.
In some cases a selection of your comments and questions will be published, displaying your name and location as you provide it unless you state otherwise. Your contact details will never be published.
Rozina Sini
BBC Your Voice
Image source, Phil WhitePhil calls the experience an "all round shambles"
I got back in touch with Phil White, who has spent a night in a hotel after his flight from London Gatwick to Lanzarote on Tuesday afternoon was cancelled.
"After nearly four hours sitting on the plane they cancelled the flight," Phil says, adding that baggage reclaim was "carnage".
"All the bags from every cancelled flight were sent to one reclaim carousel. So there were a thousand or so people trying to get close enough to get their cases," Phil says.
"The baggage hall was the worst and they're very lucky that there wasn't any sort of incident as tempers frayed and the concourse was getting hotter," he tells the BBC.
He says he's booked on a flight today at 14:15. "Fingers crossed."
Image source, Phil WhiteAll the bags from every cancelled flight were sent to one carousel, Phil says
Image source, EPATransport Secretary Heidi Alexander has summoned Nats boss Martin Rolfe to a meeting later today to answer questions about the disruption and response.
Alexander wrote on X that she would be "seeking assurances that lessons will be learned" and that current systems are "up to the job".
She will also address MPs later, where she is expected to confirm that the fault was "categorically" not the result of a cyber attack.
Rolfe earlier told Radio 4's Today programme that Nats had "ruled out" a cyber attack.