London Heathrow airport put a third runway back on its agenda as air travel begins to recover from the coronavirus crisis, triggering a backlash from climate campaigners who oppose the project.

Britain’s biggest hub, the busiest in Europe prior to the pandemic, will review growth plans over the next year after pausing deliberations during the pandemic, it said in a statement Wednesday.

The comments revive a years-long debate over an expansion of Heathrow backed by airlines and businesses but opposed by environmentalists and many London residents. Parliament in June 2018 approved a landing strip increasing the airport’s annual capacity to 142 million passengers, only for the $20 billion project to be shelved when the virus upended global travel.

Heathrow said Covid disruption strengthened its case by highlighting the facility’s importance to the economy and in guaranteeing Britain’s global connections when rival European hubs were cut off by border closures.

“The crisis has shown the pent-up demand from airlines to fly from Heathrow, as well as how critical Heathrow is for U.K.’s trade routes,” the airport said.

Greenpeace, though, said the pandemic had done nothing to make the argument for expansion, with Heathrow’s passenger tally dropping further last year even as other European hubs staged a partial rebound.

The No 3rd Runway Coalition said Heathrow’s latest results reveal its plans to be “an uneconomic fantasy,” with the airport struggling even to finance non-expansion investment amid a clash over fees with Britain’s airline regulator.

Heathrow Chief Executive Officer John Holland-Kaye said on BBC radio that passenger numbers are expected to reach pre-virus levels in 2025 or 2026. He told lawmakers in May 2020 that a new runway would only be needed in 10 to 15 years as a result of the pandemic.

The plan suffered a setback following a legal ruling that it violated climate-change policy, before the U.K. Supreme Court decided in December 2020 that the government had properly considered its commitments and that the expansion could go ahead.