The government has signalled its support for a second runway at London Gatwick airport.

The airport wants to move its northern runway, which is currently only used for taxiing or as a back up, and make it operational by the end of the decade.

Transport Secretary Heidi Alexander said she was “minded to approve” the runway if noise mitigations are put into place for residents.

The transport secretary’s approval does not guarantee the expansion will go ahead as it would still need planning permission. Some MPs, local authorities and residents are strongly opposed.

If permission is granted, work would start almost immediately, the BBC understands.

“I am issuing a minded to approve decision that provides some additional time to seek views from all parties on the provisions, prior to a final decision,” Alexander said in a written ministerial statement on Tuesday.

Gatwick is Europe’s busiest single runway airport, with more than 40 million passengers using it last year.

On Tuesday, Alexander told industry leaders aviation was good for growth.

“I am not some sort of flight-shaming eco warrior. I love flying – I always have,” she said during a speech at the annual dinner of trade body Airlines UK in London.

Alexander’s support for Gatwick expansion comes the as her government chases economic growth – with Chancellor Rachel Reeves backing a Heathrow expansion last month.

Gatwick managers say that with 55 take-offs and landings in a busy hour, the airport is “full”.

Being able to use both runways could increase the number of departures by 50,000 a year by the end of the 2030s, according to Gatwick. It says some 30,000 of those flights are planned to depart from the north runway which will only be used for departures and not landings.

Bronwen Jones, development director at Gatwick, believes a second runway would be “a win for everyone”.

She said the expansion would create more flight slots across both runways.

“That allows us to offer new routes, new airlines, more frequencies on existing routes, so that passengers have more choice.”

The work would be funded by private investment.

Sally Pavey, chair of Communities Against Gatwick Noise Emissions (CAGNE), is worried about “uncontrollable noise, ramifications on the roads, decline in air quality… and climate change.”

“We can’t keep ignoring climate change and it would be wrong to allow a new ‘bucket and spade’ runway, as we put it, at the expense of residents and the economy,” she said.

Gatwick is largely considered an airport for short-haul holiday destinations with far fewer business and long-haul flights than Heathrow.

The group would take legal action through a judicial review if the expansion goes ahead, she added.

Gatwick says it has committed to reducing noise levels to below those of 2019 – which CAGNE says was one of the worst years for noise.

Last month, Chancellor Rachel Reeves backed a controversial third runway at Heathrow, insisting it would not compromise decarbonisation targets and would be good for economic growth.

On Wednesday the government’s independent advisers, the UK climate change committee (UKCCC), recommended that to meet the country’s climate goals the amount of planet-warming gases released by the country’s aviation sector needed to fall by 17% compared to 2003 levels.

Some of the pollution from flying, it said, could be reduced by switching planes to sustainable aviation fuel (SAF) and by capturing the planet-warming gases released.

But experts think it could be challenging to obtain the feedstock, like corn grain or food waste, needed to make SAF.

The UKCCC said the best way to reduce the industry’s impact on climate change would be to significantly slow the demand for flying.

At current levels demand is expected to grow by 53% by 2040, while the UKCCC says this should be closer to 16%.

Alex Chapman from the left of centre think tank the New Economics Foundation questioned the government’s argument that Gatwick’s second runway would boost economic growth for the whole of the UK.

“This is principally an investment that will support the economy, potentially, of the region around the airport and in London and the South East, but at the cost of others,” he said.

“Does it make sense to be blowing the carbon budget on this sort of luxury good while other areas of the economy struggle?”