Opponents reckon they have colluded in making up optimistic projections about the speed with which airlines will change to yet-to-be-built clean, quiet aircraft.

ECONOMIST: Business travel

For China to truly transition to a service economy and produce products high up the value chain with real innovation--as the government has made a priority in fields like aircraft, and clean technologies--it must have the business minds that can lead the way there.

FORBES

The groups are Friends of the Earth, the Aviation Environment Federation, the National Society for Clean Air, and the Heathrow Association for the Control of Aircraft Noise.

BBC: Pollution warning on holiday flights