Gatwick airport says passenger numbers fell by 14.7 million, or two-thirds, in the first half of the year as air travel collapsed amid the pandemic.
The airport, which announced job losses earlier this week, also posted a £344m loss as sales fell across its business.
Despite signs of recovery, Gatwick said it expected air traffic and passenger numbers to remain under pressure.
It also warned passenger levels would take between four and five years to recover to pre-Covid levels.
The West Sussex airport has been hard-hit by the pandemic. Virgin Atlantic has said it will cease operating at Gatwick, while British Airways has shifted its short-haul flights to Heathrow and is cutting hundreds of ground staff jobs at the airport.
The number of travellers at Gatwick dropped by 66% to 7.5 million during the six months to June.
Gatwick said this was “due to the Covid-19 pandemic, the effects of which began to be felt during February, increasing significantly in March and causing a near-complete drop in volume during April, May and June 2020”.
Pre-tax losses in the first half of the year hit £343.9m compared with a £59.4m profit a year earlier. Sales more than halved to £144.2m.
Gatwick Airport chief executive Stewart Wingate said: “Like any other international airport, the negative impact of Covid-19 on our passenger numbers and air traffic at the start of the year was dramatic and, although there are small signs of recovery, it is a trend we expect to continue to see.”
The company also said: “The recovery period to pre-pandemic traffic levels is forecast to be four to five years.”
Gatwick has already announced plans to cut 600 jobs. About 75% of staff are currently on the government’s furlough scheme, which is due to end in October.