By Alex Kirby
BBC News Online environment correspondent
An independent UK environment advisory group says the contribution of aircraft to climate change is deeply worrying.
It wants a switch from short-haul domestic and European flights to rail travel.
It is essential that the government should divert resources into encouraging a shift from air to high-speed rail
Sir Tom Blundell
It argues for the price of an air ticket to rise, to remind travellers they are causing damage.
And it says the projected increase in demand for seats will negate technological improvements in aircraft for some time.
The warning comes from the Royal Commission on Environmental Pollution (RCEP), which reported on the environmental impact of aviation twice before, in 1994 and 1997.
The commission notes: "Neither of these reports has yet received an official response."
Slow to realise
Its chairman is Sir Tom Blundell, professor of biochemistry at the University of Cambridge.
He said: "Emissions from aircraft are likely to be a major contributor to global warming if the present increase in air traffic continues unabated.
Let the train take the strain
"The government shows little sign of having recognised that action to reduce the impacts of air transport is just as important as action in other sectors contributing to climate change.
"Instead of encouraging airport expansion and proliferation, it is essential that the government should divert resources into encouraging a shift from air to high-speed rail for internal UK travel and some intra-European journeys."
The problem worrying the commission is the emission by aircraft engines of carbon dioxide, oxides of nitrogen and sulphur, water vapour, hydrocarbons, and particles.
These are emitted high above the Earth's surface, and may affect the climate. By 2050, the commission says, aviation is likely to be responsible for 6-10% of climate change.
The RCEP says its "deep concern" about the global impacts of the rapid growth in air travel is not allayed by the "ambitious" targets for technological improvements.
Discouraging air cargo
These, it believes, will soon be overtaken by the probable increase in demand for flights, for several decades to come.
It wants aviation emissions to be included in the provisions of the Kyoto Protocol, the international agreement on tackling climate change.
Its recommendations include:
raising ticket prices by imposing "climate protection charges" for aircraft taking off and landing within Europe, and pressing for them to be adopted elsewhere
restricting airport development to encourage use by long-haul flights, while short-haul passengers are encouraged to use trains
using air freight only for high-value goods, usually perishable ones.
Paul de Zylva, of Friends of the Earth, said: "The UK's reputation for action on dangerous climate change will be dealt a hammer blow if ministers go ahead with their airport expansion plans.
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"The aviation industry pays no tax on the fuel it uses and is now the fastest-growing cause of climate change.
"Why should the rest of British business and society have to pay the penalty, just so that airlines and airports can continue to grow while ignoring their environmental responsibilities?"
The government's aviation policies have come under attack from another quarter. The Sustainable Development Commission (SDC) is its independent advisor on the subject.
Jonathon Porritt, the SDC chairman, said: "The government's approach to air transport is stuck in the old mindset of 'predict and provide'.
"But asking which airports should be expanded or built before appraising the balance of costs and benefits in any expansion programme is missing the point.
"It will be crucial to engage the public in a proper debate on how air travel fits into the broader picture of sustainable transport, and how it helps to deliver sustainable development here in the UK and further afield."
