Heathrow and Gatwick owner BAA said today the summer terror scare slashed profits by £21m (€31.3m).
BAA said the disruption to flights during the August chaos cut half-year revenues by £14m (€20.8m) and increased costs by £7m (€10.4m).
The airport operator also said it faced one-off costs of £45m (€67m)from its takeover by Spanish firm Ferrovial as operating profits for the six months to September 30 fell nearly 12% to £389m (€579.6m).
BAA came under intense criticism from the airlines in the aftermath of the terror alert, involving an alleged plot to blow transatlantic planes out of the sky.
Airlines complained BAA did not have the necessary procedures in place to keep planes flying or deal with the heightened level of security required.
British Airways saw 1,280 of its flights grounded and recently said the cost of the disruption ran to £100m (€149m).
Today’s results from BAA will be closely looked at by the Competition Commission in the expected inquiry into BAA’s ownership of airports in the UK.
Last week, the Office of Fair Trading (OFT) said the current ownership of seven airports by BAA, including Heathrow, Gatwick and Stansted, “does not deliver best value for air travellers in the UK”.
It said greater competition could bring significant benefits for passengers and indicated that it planned to request a full investigation by the Competition Commission.