Travel expert Simon Calder has explained the rights of worried holidaymakers as Gatwick is set to cancel 825 flights in July and 850 in August.
It comes amid months of airport chaos - which could last another 18 months.
Appearing on Good Morning Britain, Simon Calder tried to ease the panic of those planning to go on holiday as he shared what to do if your flight is cancelled.
Up to 800,000 people could be affected by Gatwick's announcement that they will be grounding hundreds of flights.
Speaking to hosts Kate Garraway and Adil Ray, he said of the cancellations: "It's all about a lack of resilience in the system."
Revealing that the likes of EasyJet and British Airways had already cancelled flights today, he said that it was "because they simply don't have the resources to operate them".
"Most of those passengers were told in advance," he said. "But we saw scenes here last night where, for example, there were long delays, air traffic control problems, flight to Lisbon was cancelled at very late notice and those are the sort of things that the airport is really keen to avoid.
"So it's taking this unprecedented step of saying to the airlines, 'Right, July and August we're going to cap the number of flights you can operate. That means even though you've told people they will be flying, you've sold them tickets, on some flights you're going to have to tell them that they are not travelling."
He stressed that most people would get "exactly where they want to be" and roughly on time, but warned some people over the next few days would start to get messages saying that their flights have been cancelled.
Simon insisted that holidaymakers should not panic if that is the case and it's "not the end of the world".
"You will get your holiday under the air passenger rights rules, you are entitled to get a replacement flight on any airline on the day you're supposed to at no expense to you," he said. "The airline has to pay for it."
*Good Morning Britain airs weekdays at 6am on ITV
