In their submissions to the UK's Airports Commission today, London Heathrow and London Gatwick are taking their rivalry into the issue of noise.
The commission is due to report in 2015 on how the UK can best safeguard its air connectivity.
Gatwick is arguing for a second runway, on the grounds that its point-to-point model fits the sector’s likely future pattern.
Heathrow is basing its case for a third runway on the need for hub connectivity.
But both are now aiming to win the argument over noise, a crucial issue in the debate over how London can expand its air infrastructure.
In its submission today, Heathrow states Londoners would experience less noise pollution if it gets to build a third runway.
Meanwhile, Gatwick maintains with a second runway, its noise would impact no more than 11,800 residents.
“The overall number of people who could be affected by noise from a second runway at Gatwick would be equivalent to less than 5% of the people Heathrow impacts today – mainly because aircraft would not fly over highly populated areas of London,” said Gatwick in a statement.
“This fundamental fact will not change in the future.”
But Heathrow rests its case on how next-generation aircraft such as B787s, A380s, A350s and A320NEOs can enable it to keep cutting the impact of noise on Londoners.
As well as “encouraging the quietest aircraft to use Heathrow”, the hub undertakes to route aircraft higher over the capital, and to ensure high-noise areas get periods of respite with no flights overhead.
Heathrow also vows to provide free noise insulation.
“Even with a third runway, the measures set out above mean that in 2030 there will be around 10-20% fewer people within Heathrow’s noise footprint than today,” said Heathrow in a statement.
While Heathrow operates almost twice as many flights than in the seventies, “around 90% fewer people are affected by noise”, said Heathrow’s sustainability director, Matt Gorman.
But for Stewart Wingate, Gatwick’s CEO, this is not the issue.
“The Government has made clear that its primary policy objective in this area is to limit and where possible reduce the number of people significantly affected by aircraft noise,” he said.
“Against that policy background, it seems clear that a second runway at Gatwick would be much preferable to a third runway at Heathrow; when more people are already significantly affected by noise than at all the other major EU hub airports put together.”