Campaigners against night flying have held a "sleep-in" protest to show how many hours of sleep they lose.
Campaigners claim night flights can cause health problems
They chanted and waved placards outside a London hotel on Friday where a government forum on flights at Gatwick, Heathrow and Stansted was being held.
Friends of the Earth have said about 40 planes, or about five an hour, take off or land every night at Gatwick.
Protesting residents, some in pyjamas and sleeping bags, claim the disruption can cause depression and health issues.
Most people living near the main London airports want to see very few or no flights operating between 2300 and 0700.
One demonstrator, 53-year-old accountant Graham Lee from Ruislip, west London, was dressed only in pyjamas with a thin blanket for protection against the weather.
He said: "We have chosen perhaps the coldest morning of the winter for our protest, but this shows how strongly we feel."
The campaigners include members of Heathrow anti-noise group Hacan ClearSkies, which has boycotted the forum.
Hacan chairman John Stewart said: "The idea of night flights is highly unpopular with most people.
"It beggars belief that the dinosaurs from the Department of Transport should set aside a whole day for a conference like this."
Earlier this year the government decided to extend the existing night flying restrictions at Gatwick, Heathrow and Stansted until 2005.
The quota restricts flights by the noisiest types of aircraft, but allows for more flights during the peak summer season.
The protest helped launch a Europe-wide campaign against night flying backed by Caroline Lucas, Green MEP for the South East.
"Right across Europe people are calling for a ban on night flights," she said.
"There is considerable support within the European Parliament for this."