Last September, transport secretary Heidi Alexander approved Gatwick's £2.2 billion proposal to bring its standby runway into routine use, which would allow two-runway operation at the airport.
Once fully operational, two-runway operation at Gatwick would allow the airport to go up from around 280,000 flights a year to nearly 400,000 over the next decade.
The challenges were brought by Communities Against Gatwick Noise Emissions (Cagne) and campaigner Peter Barclay, claiming the government had not fully considered the environmental impacts of allowing Gatwick airport to expand.
