The Government was being urged to clamp down on the practice after it emerged that British Airways had flown three long-haul services between London, Hong Kong and Mumbai last week, even though staff illness meant there were no passengers on board.
It is estimated that between them the three Boeing 747-400s produced the equivalent amount of CO2 to that emitted by 200 to 300 motorists in a year. Tim Johnson, the director of the Aviation Environmental Federation, said the current system of levying air-passenger duty, which charges an environmental tax of up to £80 per ticket rather than a flat rate per aircraft, provided a "perverse incentive" for aircraft to fly empty. The system is due to change in November next year.
"Moving to an aircraft-based duty is an attempt to encourage airlines to a higher pay load factor, but in the interim a carbon penalty would make up for the shortfall there would otherwise be pending its introduction," Mr Johnson said.
BA defended its decision to go ahead with the flights, saying they were carrying cargo loads and that it was the only way of preventing major knock-on disruption to passengers expecting to board return flights in India and the Far East, and of stopping delays to those aircraft awaiting fresh crew. "We operate an extremely small number of empty flights and, when we do so, we do it in order to minimise overall disruption. This is the least worst solution to a complex problem," a BA spokesman said.
However, while commercial airlines seek to operate at between 80 and 90 per cent capacity, environmentalists say they can still do better. According to figures published by the Civil Aviation Authority, British airlines flew 80 billion empty seat kilometres in 2007.
John Stewart, who is leading the opposition to the creation of a third runway at Heathrow, which will increase the number of plane movements at the airport by 50 per cent, said: "These empty flights, as far as people on the ground are concerned, are still making noise and as far as climate change is concerned they are still spewing out CO2."
The Liberal Democrat environment spokesman, Steve Webb, backed calls for an interim levy on empty flights. "It is a stop-gap measure to stamp out this abhorrent practice pending a rationalisation of landing slots at UK airports," he said.
© 2008 The Independent