Heathrow has announced that its cumulative losses from the COVID-19 pandemic have hit £2.9 billion ($4 billion). Fewer than four million passengers travelled through the west London airport in the first half of the year. It took just 18 days to reach that total in 2019. The airport warned that its passenger numbers could be lower this year than in 2020. Some 22.1 million passengers used the airport in 2020, with more than half of those travelling in January and February before the virus crisis led to a collapse in demand. Heathrow described recent changes to the quarantine and testing requirements for people arriving in the UK as “encouraging,” but warned that the rules are “holding back the UK’s economic recovery.” The airport’s chief executive, John Holland-Kaye, said: “The UK is emerging from the worst effects of the health pandemic, but is falling behind its EU rivals in international trade by …