Flights returning 110,000 holidaymakers from overseas after Monarch's collapse will cost about £60m, according to the UK airline regulator. Transport Secretary Chris Grayling has called the flights the UK's biggest repatriation exercise in peacetime.
Monarch Airlines ceased trading on Monday and all its future flights and holidays have been cancelled. Administrators said 1,858 Monarch workers had lost their jobs on a very sad and difficult day.
The Civil Aviation Authority (CAA) hopes that about 12,000 customers will be flown home on chartered planes by the end of Monday. The government is set to pick up the tab for the UK's biggest ever airline collapse, but is talking to card companies about sharing some of the cost.
Theresa May's official spokesman said the prime minister feels hugely sorry for those affected by a very distressing situation.
Monarch - the UK's fifth biggest airline - was placed in administration at 04:00 BST - a time when the airline had no planes in the air. Passengers were then sent text messages informing them flights had been cancelled - but some customers were already at airports.
Monarch, which reported a £291m loss last year, had employed about 2,100 people. About 250 staff have been retained to help with repatriation efforts. Terror attacks in Tunisia and Egypt, increased competition, and the weak pound have been blamed for Monarch's demise.
Monarch reported a loss of £291m for the year to October 2016, compared with a profit of £27m for the previous 12 months, after revenues slumped.
Blair Nimmo, from administrator KPMG, said its collapse was a result of depressed prices in the short-haul travel market, alongside increased fuel costs and handling charges as a result of a weak pound. However, Monarch chief executive Andrew Swaffield said the root cause was terrorism in Egypt and Tunisia, as well as the collapse of the market in Turkey.
Monarch's owner, Greybull Capital, had been trying to sell part or all of its short-haul operation so it could focus on more profitable long-haul routes, and said it was very sorry it had not been able to turn around its fortunes.