LONDON (AP) — British airport operator BAA Ltd. estimates the volcanic ash cloud which grounded flights at its two London airports will cost it £28 million ($42.5 million) this year.

The company said earnings before interest, tax, depreciation and amortization, or EBITDA, in the first three months of the year were £174.1 million, up 3.3 percent from a year earlier.

The airspace closures caused by ash from Iceland's Eyjafjallajokull volcano prompted the cancellation of about 100,000 flights worldwide. Heathrow and Stansted were closed from April 15 to April 20, and traffic returned to normal only two days later, the company said.

Chief executive officer Colin Matthews described the London airports' performance through the first three months of 2010 as "resilient," despite bad weather and strikes by British Airways cabin crews. BA is the company's largest airline customer.

"Operational performance in the quarter was robust despite enhanced security procedures, extreme winter weather and industrial action at our biggest airline customer," Matthews said in a statement.

"The rest of 2010 continues to present significant financial challenges for the industry as a whole.

"We currently estimate that the closure of Heathrow and Stansted due to volcanic ash will have a total impact on 2010 Adjusted EBITDA of 28 million pounds."

BAA, which also operates airports in Scotland and England, is owned by a consortium headed by Grupo Ferrovial SA of Spain.