Dear Sir/Madam,

I read George Monbiot's article, "A weapon with wings" in Tuesday's Guardian, and chanced to hear him during the day on BBC 2 radio. His view I find a valid one, as well as being in interesting and welcome contrast to more conventional views. But he misses, or certainly fails to emphasis, the essential and most dangerous aspect of air travel: its fundamental non-sustainability on a planet with limited natural resources and carrying capacity, which will soon be populated by 7-9 billion people, the vast majority of whom, once they can afford it, want to fly; just as they want to own and drive their own motor cars.

Our planet, Spaceship Earth, cannot support either form of modern transportation on the scale that human inclination and "economic necessity" are inexorably taking us toward.

We are flying and driving ourselves towards extinction (or something horribly close to it), yet are unwilling or unable to face up to the fact.

Why? Because (for understandable behavioural and historical reasons) our economy is based and dependent on our compulsive, more animal than human nature. If we could but see it, we are quite literally addicted to and dependent on the materialism, commercialism and consumerism which are causing us to plunder and spoil our planet, and which will lead to our demise if we do not make some radical and rapid changes to our way of life. Just as substance addiction will eventually destroy an individual, so society's addiction to a growth-dependent economy and insatiable consumerism is certain to destroy our civilisation.

With hindsight, we shake our heads at the blindness and stupidity which led to the horrors of the 20th Century (Homo sapiens, indeed!), yet we have learned so little that now we ourselves are boldly striding towards even bigger calamities, perhaps even The Final Calamity, specicide and extinction.

By missing, or failing to emphasis, the essential point of non-sustainability, Mr Monbiot is simply adding to the confusion and making it even more difficult for people to face up to the dire situation we are in.