Airline passengers have been contacting the BBC to complain about luggage that has gone missing since air security was stepped up after news of an alleged terror plot.
Delays at Heathrow continued over the weekend
Here are some of the stories passengers have told us about their experiences of losing their luggage and the response from the airlines.
Marie Henley, together with her partner and one-year-old daughter, flew from Heathrow to Brussels on Friday, arriving back in London on Saturday evening.
The family were asked to pack keys and mobile phones in suitcases.
"The luggage never arrived at Brussels, but we understood that there might have been a problem and just dealt with it.
"But returning to Heathrow, it was just so chaotic - worse than when we'd left.
"Having spent several hours trying to claim our bags, we abandoned the car at the airport because the keys were in the luggage as requested.
"We queued for ages for a taxi - which cost £60 - and travelled home obviously with a distressed baby and had to smash a window to get into our house in the dark on Saturday evening because both sets of keys were in the baggage as requested."
Matthew Ward, who is disabled, was flying from Nice to Luton on Saturday.
An airline assistant had helped him onto the Easyjet plane and told him his wheelchair would be put in the hold.
Mr Ward does not expect to see his wheelchair again
However, it did not arrive at Luton and Mr Ward says he cannot live without it.
"I have not got the wheelchair back yet, but I have been chasing it and ringing Easyjet.
"At the moment, from the last time I spoke to them, my wheelchair might not even be in Nice Airport.
"It might be at a different airport in Europe.
"Regardless of the stress they were under, and that is not their fault, they should not be so careless.
"I have borrowed a neighbour's wheelchair but it is not one I can pull myself up on.
"I am hoping to get my wheelchair back but I am not expecting it back. It does not look good at the moment.
"It has been a nightmare."
Michelle Pierce from Maidenhead flew up to Edinburgh at the weekend.
The last time she saw her bags was when she checked them in on Friday evening.
"A large majority of the people on my flight did not receive their bags.
"We have no information about the whereabouts of our bags; apparently they do not know where they are and there are too many lost bags at Heathrow for them to go and search for individual ones.
"I could cope with the delays and flight cancellations (I experienced both), but am feeling very frustrated at the airport for letting us fly when they knew that our bags would not be going with us.
"Especially as the extra security meant we had no hand luggage to help us get through the weekend, including of course our mobile phones."
Natalie Brown flew to Frankfurt on Friday night.
Her original flight was cancelled and the flight she managed to get on was two and half hours late.
When she finally arrived in Frankfurt, she found out her bags had not travelled with her.
"Half of the plane did not have their bags.
"I was told I could get my bag in London on my return as it was still there.
"When I arrived in London, I was told I could not get my bag as there were 20,000 bags 'lost'.
"It is now the fifth day and BA still cannot tell me where my bag is - it has my house keys, mobile and work pass."
Michelle Brown flew into Heathrow then on to Edinburgh at the weekend.
She said only a handful of the 200 passengers on board her flight were able to pick up their luggage after they landed.
"The captain said there's two people on the plane that we've got bags for, but the people aren't here, they hadn't made the connection so we have to take the bags off," she said.
"So we waited about 45 minutes and they said we've got about 180 bags to sort through and then he said that's ok, we've found the two bags, we've taken them off and we're ready to go.
"So when we got up there, and there was no bags there, it was clear that they'd just taken them all off."