Thomas Cook customers accused the airline of withdrawing cash for the disappearance of a holiday company after facing high bills to book a replacement flight.
Those who booked flights with the company now told the BBC that the price of a flight has tripled in some cases to find an alternative deal.
Holiday maker Angela Mills said the flight from Glasgow to Death to Greece is 280 pounds on Sunday, but now it's 1,000 pounds.
Analysts said the price reflects high demand for routes with few spare seats.
John Strickland, aviation analyst at JLS Consulting said, “People are not sitting with their hands up in joy. The price rises when sales increase sharply on popular routes.
Strickland said September is a popular time for people to enjoy holidays, not school closures, and many flights are already full.
He said airlines could decide to stop the price increase, but the company said it should be promoted commercially.
"Thomas Cook failed because he had a huge debt and lost money. It's a vulnerable industry. More than 12 airlines went bankrupt.
"If the airline doesn't benefit from having a few flights available, there's no chance of survival."
But Mrs. Mills said that this increase is not good for travelers who are already "in shock."
She flew from Glasgow to Rose on Wednesday Thomas Cook flight. When the travel agency found an alternative after the collapse, the cheapest price to find an alternative flight for her and her husband was over £ 1,000.
The company where she booked accommodation through Jetline Holidays eventually found an alternative deal that cost her an additional fee of £ 600.
But she now has to catch a plane in Edinburgh, and when she returned, she spent the night in Prague and returned there.
Mrs. Mills says she hopes to incur additional charges for the flight when she returns.
What are my rights?
Anyone who purchases a future package vacation with Thomas Cook is subject to the air travel organizer's licensing scheme (Atol). This means they won't leave but holiday costs will be refunded.
However, Atol protection does not apply to flight-only transactions. The main alternative for travelers is to claim a refund or charge travel insurance from a used credit or debit card provider.
What are your rights? See here for details
Kevin Spence went to Florida with his family next June. It took two years for the trip and planning.
But he said Thomas Cook rose sharply the next morning while checking flight prices just before it collapsed on Sunday.
The original flight cost of £ 1,800 per four members of his family has now risen to £ 2,500, he said.
"I am devastated.
"Holiday costs are over the current budget. I am now in a position to cancel it completely," he said.
But Nigel Wilson said he could beat the price increase by booking a new flight for a vacation from Manchester to Marrakech on Monday at 12:30 am (BST).
The cost of flying for four families added 640 pounds, but when checking prices on Monday, it said the cost rose to 1,500 pounds.
"If we waited, we wouldn't have the funds to book more tickets at that price," he said.