The convenience and independence of a car is viewed practically as a birthright, with most of us wanting our own private transport.

But when it comes to our holidays we're signing up in droves for a troublesome, awkward form of mass transport.

Flying used to be reserved for the affluent, with old Aer Lingus brochures from the 50s and 60s marketing the experience as akin to staying at a flying hotel. But today, no-frills airlines pack us in with promises to bring us St Petersburg for the price of half a bag of crisps and a Mars bar.

By last year passenger numbers at Irish airports stood at 17 million, and the number is projected to nearly double by 2016, to 30 million. This signals greater freedom of movement, but at a price. Aircraft produce 19 times the greenhouse gas emissions of trains, and 190 times that of ships.

As a result, environmental groups say that limitations must be placed on the proclivity of people to fly. "But the approach can't be, 'Thou shalt not fly to Florida this year'. That won't work, it's a free country," says Éamon Ryan, Green Party transport spokesperson.

The French government has proposed a direct tax on jet fuel. Ryan thinks an equally promising approach is the EU Commission's recent proposal to extend the emissions trading system to the aviation sector, forcing airlines to pay for excessive carbon emissions. He believes the cost wouldn't be prohibitive, with a US flight €30-50 dearer.

Aviation could contribute 15 per cent of greenhouse gases each year if unchecked, environmentalists warn. And emissions at altitude have 2.7 times the environmental impact of those on the ground.

Another part of the solution is greater fuel efficiency. The giant Airbus A380, which first flew last April, could lead the way. It's the largest civilian aircraft ever built, and when it comes into service next year it will have a typical passenger payload of 555, compared to 416 for the Boeing 747. So the ratio of passengers to fuel will be higher, and the Airbus also burns 12 per cent less fuel than the 747.Some airlines may fit their planes out to carry the maximum permitted number of passengers, a whopping 840. When you're crammed in among them, won't you wish you were back on the auld sod, dipping a cold toe in the water at Bettystown?