London Heathrow airport raised its passenger forecast but warned that demand is likely to drop off later in the year as a summer boom gives way to a “winter freeze.”

The airport, Europe’s biggest hub before the Covid-19 pandemic decimated travel, raised its annual passenger forecast by 16%. Even so, it will remain unprofitable this year after total losses from coronavirus disruption reached 4 billion pounds ($5.1 billion).

While the U.K.’s decision to drop Covid-related curbs sparked a travel surge over the Easter holidays, demand is volatile, the airport said in a statement Tuesday. Airlines are already canceling services into the fall, and higher fuel costs, a slowing economy and the impact of Russia’s war in Ukraine on bookings for flights to Europe will drag on the comeback, Heathrow said.

“There’s a huge amount of uncertainty,” Chief Executive Officer John Holland-Kaye said in an interview. “A lot of the demand that we’ve seen coming through involves people cashing in vouchers or taking postponed journeys. In a worst case scenario this wouldn’t continue, and we’d see a new wave of coronavirus in the autumn.”

Source: Civil Aviation Authority – Qatar