Last month's terror security alert cost airports operator BAA more than £20m, the company is set to announce.
Passengers suffered long delays after last month's alert
Thousands of flights were cancelled at Heathrow and BAA's other UK airports after an alleged plot to blow up transatlantic flights was foiled.
Tight security measures introduced after details of the plot emerged caused chaotic scenes at many airports.
BA, which criticised BAA's handling of security at the time, has already said flight cancellations cost it £40m.
On Tuesday BAA, which operates Heathrow, Gatwick, Stansted, Glasgow and Edinburgh airport among others, will outline the cost of the alert to its business when it publishes details of passenger figures for August.
The £20m figure is more than double the loss BAA suffered as a result of last year's industrial dispute at catering firm Gate Gourmet, where disruption was limited to Heathrow.
Following the alert on 10 August, passengers were barred from taking any hand luggage onto planes, except for one small plastic bag.
Although the rules were subsequently relaxed, allowing people to carry one item of hand luggage the size of laptop computer on board, the security measures were fiercely criticised by airlines.
Ryanair is seeking £3.3m in compensation from the government, claiming the restrictions were excessive, unevenly applied and damaged its business.
BA, which cancelled more than 1,250 flights between 10 and 17 August, has also said it is considering seeking compensation.
The £20m cost of the alert represents only a small fraction of BAA's annual sales of more than £2bn a year.
But the impact the alert will have on people's willingness to fly in the longer-term is harder to verify and remains a potential concern to BAA's owner, Spanish company Ferrovial.
The alert came at a boom time for British airports with a record 15 million passengers using BAA airports in July.