There's a call for the urgent introduction of so-called "aircraft superhighways" over the South East.
An industry campaign claims the new narrower flight paths are vital to increase capacity and reduce pollution.
But Gatwick anti-noise campaigners say such changes would cause misery for thousands of people living around the airport.
People fighting plans for airport expansion in the South have begun to gather outside the House of Commons ahead of an official government announcement on the matter.
The Government's preferred choice for the location of a new runway or additional capacity for aeroplanes and flights - will be announced at 12.30 this afternoon.
Heathrow Airport says it will create 5,000 new jobs over the next five years if it gets approval for a third runway. It also plans a controversial congestion charge and a ban on night flights before 0530.
The airport revealed radical expansion plans today ahead of a possible third runway that could open in 2025. The plans will be subject to consultation and Government approval.
It will also spent tens of millions of pounds on insulation and other measures to help reduce nose for residents.
Overall flight numbers will rise by 25,000 a year with four million more passengers. The airport says new technology will allow this without causing more delays for existing flights.
The airport says the measures will help keep Britain competitive after Brexit with new links from airports in the UK and around the world and it will help boost the economy.
The measures are dependant on a third runway being approved. Gatwick, meanwhile, wants its plans approved - for a second runway - rather than Heathrow.
While the restriction on night flights will be welcome the 25,000 extra flights a year will be seen as extra noise and misery for hundreds of thousands under the flight paths by critics.
Here are the main points from the proposals to be implemented by 2021 ahead of a third runway being approved. Full details will be revealed at the Tory conference on Monday.
- Estimated 5,000 new jobs.
- £1.5 billion pound boost to the economy after Brexit.
- 25,000 extra flights a year. New technology and better use of existing runways will achieve this.
- Four million extra passengers a year.
- Congestion charge considered. This could be a new drop-off charge, increased car parking charges or a scheme similar to congestion charging in London. This is to help reduce emissions, fund new public transport initiatives and ensure fifty per cent of passengers arrive by public transport by 2030.
- No night flights before 0530 which is an hour later than at present
- £60 million spent on noise insulation for homes under the flight path
- New monitoring equipment to ensure noise levels are not broken.
- Better facilities for cyclists, electric cars and green transport.
Campaigners against an expansion of Gatwick Airport say plans for a second runway are "horrendous" - and much larger than they were led to believe.
The proposals - set out in a 3000 page document - have been sent to the Airports Commission but have NOT yet been published.
It would see Gatwick almost triple in size - with passenger numbers up to 97 million a year - thats bigger than Heathrow. From Westminster - our Transport Correspondent - Mike Pearse sent this.
The Travel expert Simon Calder gives his opinion on today's Davies report on airport expansion.
London Mayor Boris Johnson has suggested that a new Kent airport could trigger major expansion. On his tour to India he said an offshore airport in the Thames Estuary may lead to schools, hospitals and further development.
We have an interview with Boris Johnson in India and response from Kent MPs Gordon Henderson and Mark Reckless - plus Kent County Council leader Paul Carter.
Southend Airport in Essex is to open a new terminal at an official ceremony on Monday. Passengers have been using the terminal since 28th February. The site is expected to handle an extra 2 million passengers a year by 2020.