Heathrow Airport has promised to reduce night flights and curb both noise and pollution if it is allowed to build a new, third runway.
The pledge comes ahead of a government decision expected this summer on whether to expand Heathrow or Gatwick.
Gatwick Airport said it remained the “only expansion plan that could deliver for the UK”.
Last year, the Davies Commission recommended expanding Heathrow, but with strict environmental restrictions.
The inquiry led by Sir Howard Davies recommended a ban on night flights, limits to overall noise and guarantees that local pollution would not get worse.