LONDON — The main international airline lobby group has complained to the British government about its handling of the volcanic ash cloud that is disrupting air traffic.

The Geneva-based International Air Transport Association said it found it “astonishing and unacceptable” that Britain’s aviation regulators did not have their own Cessna aircraft to gather data on the ash plume.

The U.K.’s Civil Aviation Authority says it relies on forecasts by Britain’s official weather forecasters, the Met Office, for information on the ash.

IATA’s chief executive Giovanni Bisignani said he is also concerned about the lack of formal agreement between governments over how to regulate their airspace.