The information, obtained through a request for freedom of information from the Guardian, shows that Heathrow, Aberdeen, Manchester, Stansted and Norwich were the top five airports for such flights during the season. Ghost flights are defined as those that do not have passengers or less than 10% of passenger capacity. Data from the Civil Aviation Authority only includes international flights departing from the United Kingdom and not domestic arrivals or flights. Flights are one of the most polluting activities that humans can do and ghost flights have angered those struggling to take action on the climate crisis. Nearly 15,000 ghost flights flew out of the UK between the start of the Covid-19 pandemic in March 2020 and September 2021, the Guardian revealed in February. German airline Lufthansa said in January it would have to operate 18,000 “unnecessary” flights by March. Such flights have been blamed on the system at busy airports, where airlines normally have to operate 80% of their flights, empty or not, to maintain their landing positions. The rule was suspended during the pandemic and returned to 50% in October 2021, but this does not seem to have significantly changed the number of monthly ghost flights. An average of 500 climate-harmful ghost flights departed from the UK each month in 2021 Tim Johnson, of the Aviation Environment Federation, said: “The average occupancy of UK airlines has grown significantly in the last six months of 2021, although the November peak at around 70% is still well below the 86% had been achieved before the pandemic. But that has not changed the number of extremely low-flying flights in our skies each month. “If changing the fate of the market cannot solve this problem, then the government must act to do so,” he said. “Her recent claim earlier that aviation may be purely zero by 2050, while it can accommodate a 70% increase in passenger numbers (from 2018 levels) strengthens the belief when there are such obvious examples of inefficiency in the current system. “Correcting them must be a priority.” The government regulates aviation, but no figures have been released for the number of ghost flights. Only airlines know the actual number, but did not provide this information when asked by the Guardian. “The public deserves transparency,” said Sarah Olney, a Lib Dem MP and transport spokeswoman. “They do not take it from an industry that keeps this cunning practical silence, and ministers must share the responsibility for this serious accountability gap. “A government review of ghost flights is long overdue.” Alex Sobel, a Labor lawmaker and chairman of the All-Party Pure Zero parliamentary group, said: “enhance their practice of climate-degrading ghost flights.” A parliamentary petition calling for the termination of such flights has been signed by 14,000 people. The Ministry of Transport said: “We acted quickly [during the pandemic] to avoid the need to fly an aircraft license to maintain their seats, however some flights may operate with a low number of passengers for a variety of reasons, including the transport of key workers or vital cargo. Airlines UK, the UK-based airline commercial operator, said: [CAA] The numbers reflect two things – renewed travel restrictions to combat the Omicron variant, leading to flights from destinations such as Morocco and the Far East that bring UK travelers home. “Passenger aircraft have also been widely used as cargo during the pandemic, and although these flights carry basic goods and supplies, including PPE, they will be inaccurately classified as ‘ghost flights’ in this analysis.”