By Daniel Mann
BBC News Online
Cheap flights on no frills airlines may not be a burden on our wallets but they will dearly cost the UK's environment, campaigners believe.
Ryanair keeps costs low for passengers
Scientists predict that if carbon dioxide emissions continue to increase, global warming will bring higher annual temperatures and heavier rainfall - with all the associated problems.
But with air passenger growth expected to rise at 3-5% a year, it is going to be very hard for Britain to meet its targets for reducing gas emissions.
Agencies such as the Sustainable Development Commission (SDC) want our air tickets to reflect "the true cost of flying" to the environment.
To green groups, this involves the aviation industry having to pay tax on the fuel it puts in planes.
According to Friends of the Earth (FOE), the absence of fuel duty effectively gives the industry a £9bn annual subsidy.
And it gets this "help", the FOE says, even though planes contribute 5% to the UK's carbon dioxide emissions, with the figure set to more than double by 2020.
"The vast majority of flights are discretionary, for leisure," says Richard Dyer, the FOE's aviation campaigner.
"These are not essential, unlike travelling by bus where you don't pay tax on a ticket.
"A starting figure would be the equivalent of tax that is charged per litre on car fuel. Passengers should pay for the environmental damage that they're doing to ensure a safer environment."
Any policy on aviation fuel tax has to be agreed internationally, according to the SDC.
Unlike in the US where a large number of domestic flights emit carbon dioxide over one area, the SDC has said that 97% of UK air transport is non-domestic, with carbon dioxide emissions generated on flights between countries.
This situation makes it difficult to assess different countries' responsibilities.
More of us are flying now and will be in the future
The Kyoto Protocol and the UK government's energy White Paper targets do not currently cover emissions from international aviation, as there is no global agreement on the allocation of these emissions to countries.
But Bernard Bulkine, the chair on Energy and Transport with the SDC, says the issue will eventually have to be addressed.
"Air transport has increased twice as fast as road transport over the last 40 years. There are clearly environmental effects increasing as a result of air travel, while others are decreasing or staying constant.
"What we have to look at is how environmental costs are incorporated into ticket prices. That's the issue, not whether there should be an aviation fuel tax. Obviously this should be done."
To the airline industry, the fact that it has to operate in a global market place, with all the stresses and strains that comes with international competition, is a key issue.
And although the industry is not taxed on the fuel it uses, for the last 10 years passengers have had to pay a £5-10 charge on a ticket depending on the destination.
The industry believes this Air Passenger Duty (APD), which raises £800m a year, can be regarded as a form of environmental compensation.
"The APD is an environmental tax," says Jan Skeels, secretary-general of the European Low Fares Airline Association.
"Imposing additional environmental costs will hit low-costs carriers much more than the major carriers. An aviation fuel tax would be just yet another tax."
The British Airport Authority (BAA) believes any aviation fuel tax will have to be an international one, otherwise UK airlines will have to compete against carriers who can offer lower fares not subject to the duty.
"It may not mean that the industry would be destroyed, but there are much more efficient and effective tools when it comes to dealing with emissions," says Caroline Corfield, from BAA.
"Since April this year, airlines that use Heathrow Airport have been charged for nitrogen oxide emissions and carriers emitting less receive a rebate. This will happen in Gatwick in a year or so."
One other possibility that has been put forward by the airline industry is emissions trading.
Under this scheme, to help with the environmental costs caused by civil aviation pollution, by 2008, the industry would pay for other industries, such as the nuclear fuels sector, to reduce their carbon emissions.
The proposal has been put forward to the European Commission, and includes an incentive for airlines to pay less into emissions trading if they use more environmentally friendly aircraft.
The FOE says emissions trading, and the proposal to differentiate landing charges at airports according to noise levels and air pollution, outlined in last year's aviation White Paper, has potential.
Motorists are clobbered by tax compared with airlines
But it accuses the government of abandoning its environmental responsibilities.
Mr Bulkine says the issue of an aviation fuel tax is not top of the international climate change agenda, because it will have to be confronted at a global level.
"There are a lot of domestic issues the government has to deal with, areas that damage the environment more than the 5% of carbon dioxide emissions caused by the airline industry," he says.
On this basis, the likelihood of low-cost air fares rising in the near future is an unlikely one.