High-density charter companies pack the punters in tightly, and operate with much higher "load factors" (average number of seats occupied) than scheduled airlines. The result: a much lower per-person impact on the environment and the airport's neighbours. Your knees may be numb but your conscience should be clearer You might also become a bit of a planespotter. Generally, the more modern the aircraft, the more quiet and efficient the engines.

Even if there is no alternative to flying, there are ways to limit the damage - and that mainly means opting for the most efficient option. GETTING THERE Better: If there's a train or a boat or a bus, choose it in favour of the plane. Flying devours finite resources, makes a fearful row and pumps poison into the atmosphere. The singer once condemned a raucous crowd with the words: "You're behaving like tourists," - the biggest insult she could muster. On the scale of damage caused by global industries, though, tourism is one of the more benign businesses.

For now, most of us will settle on a messy compromise, seeking to limit our impact without restraining our horizons. Whatever your style of travel, the decisions you take can make a real difference to the physical and mental health of the planet, and sustain it for future trips - and future generations Here are a few examples of better and worse choices. Yet to do so is to forego something that most of us regard as a right - and to deprive the millions of people in the rest of the world who depend on tourism for a living Joni Mitchell is not fond of holidaymakers. Anyone who is absolutely serious about limiting the environmental impact of their holiday should walk or cycle around their local area, perhaps camping or staying in a bed-and-breakfast. The result: too many of us burning up aviation fuel while chasing the sun, seaside and sights Tourism also impacts on communities.

This can be anything from distorting the labour market - with workers abandoning the fields or the fishing boats for the richer harvests of tourism - to diverting scarce resources such as water to benefit tourists - to the detriment of local people. The same dynamic is happening across Europe - especially in the east, where the desire to see the world was artificially constrained for decades. And the burgeoning middle classes in India, Brazil and China are adding tens of millions to the international jetsetters keen to see the planet before all those pesky tourists diminish it. The average British wage earner can comfortably bring home enough in seven days to fly to Australia and back. Now travel to Europe has fallen to the same price bracket as a good dinner out, we are becoming steadily more addicted to abroad - to the considerable detriment, incidentally, of the UK Treasury. Into the bargain we consume scarce resources and trash the environment.

Worse still, we distort and sometimes destroy the coherence of communities. Even the sensitive traveller's mantra -"take only photographs, leave only footprints" - raises concerns. How much energy did you consume to reach the location you photographed? And from the Pennine Way to the Inca Trail, paths are deteriorating under the cumulative impact of millions of footprints. So is there such a thing as a "good" tourist? As with many enigmas, the answer is as opaque as the jet trails from the thousands of aircraft that are flying tourists around at any one time We are living in an age when our horizons are limitless. Being a responsible tourist is like walking on environmental eggshells. By going on holiday we run the risk of destroying the very things we wish to see. The obstacles are ignorance and our human resistance to change.