The USA's Federal Aviation Administration (FAA) has waived slot use rules at New York John F. Kennedy and New York LaGuardia airports plus at Washington Reagan National until March 27, 2021, while flights at Chicago O’Hare, Los Angeles, Newark and San Francisco airports are 'partially protected' through March.

Without the waiver, airlines would have to fly 80 per cent of their schedules or risk losing those slot rights.