CHEAP flights are alluring. A bit like walking into an empty bank with the safe wide open, they encourage you to do something you know is probably bad, but terribly hard to resist. Why bother with the high street or the shopping centre when you can fly to New York for the weekend for less than you will spend on designer "bargains"? If you like culture rather than retail, then hop on a flight to Rome, or Prague, or Madrid to check out the galleries.

Why restrict yourself to booze cruises to Calais - so last century - when you can inflict your raucous stag night on the inhabitants of some newly-discovered "cheap" destination city? Cheap flights encourage us to be greedy, to load up our personal goodie bags with foreign experiences and hot weather. Scottish winters are a downer, so why not buy a second home in some more clement foreign spot, a possibility only made feasible because some budget airline has struck up a deal with the local mayor and chamber of commerce to attract foreign cash using cheap flights as bait.

This the sort of thing that Ed Miliband, our climate change and energy secretary, has in mind when he talks of the "right to fly". While the environmental lobby, recognising the role of aviation in fuelling global warming, calls for fiscal disincentives, Miliband seems intent on drumming up business for the Ryanairs and easyJets of the world. Rather alarmingly, given his job title, he intends to exclude aviation from government measures to reduce carbon dioxide emissions by 80% by 2050, because he thinks it would be unfair if only rich people could afford to fly.

Miliband's spirited Carry On Flying defence is couched in words of social inclusion: "People ... have benefited from ... foreign travel which, 40 years ago, only the middle classes took for granted," he says, in apparent ignorance of Department for Transport statistics which show that just 10% of the UK's population takes half of all the flights from these shores. And we're not talking here about the blokes that empty our bins. According to the Aviation Environment Federation, the average yearly household income of passengers using Stanstead, hub for budget airlines, is £47,000.

No, wholesale environmental vandalism with wings on is the preserve of people who aren't short of a bob or two. First at the check-in desk are those who never for a second consider the train or bus alternatives, even for trips within these isles.

Last year, 56% of flights from Heathrow were to domestic or short-haul destinations. They are filled with nice, respectable, decent citizens who consider themselves too busy, too important or too posh to get a train or a bus, many of them business people or academics who could easily convene their meetings by email or conference call. Only a tiny minority of regular plane users have a legitimate excuse, such as age or infirmity. After all, navigating airports - queues, long walks etc - presents a challenge to all but the most able-bodied.

The travel industry tries to justify its heavy carbon footprint by citing the notional economic benefits that tourism brings to countries and communities, such as the Maldives, that have little else to offer than their climate and natural environment. The irony here is that these atolls are in the front line for disappearing under sea level if global warming continues unabated. The Maldives cannot welcome the heavy carbon footprint of plane-loads of 21st-century tourists without conniving in its own downfall.

I once interviewed Dr Sean Carrington, a professer at the University of the West Indies in Barbados. He was adamant that his island's environment could not cope with Costa del Sol or Cancun-style mass tourism. Only rich people's tourism, he said, was beneficial to countries like his. If you are loaded enough to check into the famous Sandy Lane Hotel, where some 800 staff service the high-spending occupants of 112 rooms, then you're helping the local economy by way of employment.

The same is not true of canny, retired second-home owners getting by on depleting pensions, or frugal backpackers who make a virtue out of spending as little as possible. Brutal though it may be to hear it, the world's most fragile spots need small numbers of rich tourists, not plane-loads of canny middle-class bargain-hunters arriving on budget flights, ticking off countries on some "must-see" list as they go.

Ed Miliband says that making air travel more expensive would see Britain reverting to "1974 levels of flying", which is probably what needs to happen if we are serious about tackling this fastest-growing source of greenhouse gas emissions. And if we care about social equity, then giving every citizen a carbon budget is the obvious way to achieve that. Like other bad habits, addiction to cheap flights is hard to give up, so we need to be saved from ourselves.