ITV News' Rebecca Barry heard how destination weddings and family holidays have been ruined due to delays and cancellations.
There are warnings that disruption at the UK's travel hubs could get "worse before it gets better" this summer, as unions pointed to "staff shortages across the industry".
Airline passengers have faced long delays and cancellations at airports for several months, with the situation appearing to worsen this week as half-term holidays and the Platinum Jubilee bank holiday period create a perfect storm.
Aviation data firm Cirium said 291 departures from major UK airports have been cancelled between May 25 and Tuesday.
Manchester airport said Tui and its ground handler, Swissport, are suffering from staff shortages and are experiencing “significant challenges with their check-in and baggage reclaim operations”.
ITV News reporter Ellie Pitt explains how Transport Secretary Grant Shapps plans to 'get tough' on travel companies in the wake of the chaos.
A Tui spokeswoman said: “We would like to apologise to our customers who have experienced flight disruption in recent days and understand that they have been looking forward to these holidays for a long time.
"Unfortunately, due to ongoing challenges in our operation, we have had to announce a small number of planned cancellations between now and 30 June from Manchester Airport only.
"We are directly contacting all impacted customers in departure date order and they will automatically receive a full refund.
"We can reassure our customers that the remainder of our flying programme is expected to operate as planned.
"We’d like to apologise again for the inconvenience caused and we thank customers for their understanding and patience during this time."
British Airways is continuing to cancel dozens of flights each day, although the airline said passengers are being told several days in advance.
Video shows long queues at Heathrow's Terminal Two
Garry Graham, deputy general secretary of the Prospect union warned that due to "staff shortages across the industry", disruptions to travel "could get worse this summer before they get better."
A spokeswoman for the government insisted the aviation industry is "responsible for making sure they have enough staff to meet demand" but opposition MPs have said the government needs to do more to address the issues.
Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To know...
Passengers at airports such as Heathrow, Gatwick and Bristol are reporting long delays as the aviation industry suffers from staff shortages caused by thousands of people being let go during the pandemic.
Many airlines and airports repeatedly called for more financial support due to the collapse in demand for travel caused by the Covid-19 crisis.
They are now struggling to recruit new workers and have their security checks processed.
"We have more vacancies than we have candidates," Kully Sandhu from the Aviation Recruitment Network said.
Travel journalist Simon Calder told ITV News: "The airlines desperately wanted to sell lots of tickets because they need to start paying back the billions of pounds that they owe and, unfortunately, they haven't quite got the resources to do that - and neither have the airports got enough staff in place."
Transport Secretary Grant Shapps introduced legislation last month to allow new aviation recruits to begin training before passing security checks to reduce the time it takes for them to start work.
A government spokeswoman said airports are “busier than usual” due to “an exceptionally high number of people travelling” this week.
She continued: “The aviation industry is responsible for making sure they have enough staff to meet demand and we have been clear that they must step up recruitment to make sure disruption is kept to a minimum.
“In addition, using our post-Brexit freedoms, we have changed the law to provide the sector with more flexibility when training new employees, which will help it to fill vacancies more quickly.
“We have also worked with Border Force to ensure preparations meet passenger demand.”
Travel chaos wasn't limited to just the skies today, as Eurostar passengers were forced to wait for hours in a queue that snaked along roads outside London’s St Pancras station.
One Eurostar customer speaking to PA described the situation at St Pancras as a “total shambles”, adding: “Thousands of people, queues snaking around the station, out into the street and back in again. Shocking mismanagement.”
Another traveller complained about “waiting outside in the rain” and there being “no clear signs and explanation”.
Eurostar said in a statement: “Unfortunately we had a technical fault on a train earlier this morning which meant we had to take it out of service.
“As a consequence, there are delays of 30-60 minutes on departure in London St Pancras.
“Queues are moving and our staff are working hard to look after passengers and ensure their check-in is as smooth as possible.”