The comparison was inappropriate, and some would say laughable.
But on 28 May the Independent newspaper in Britain carried a set of comparisons that can help more informed thinking and reflection on the impact of flying.
* Air travel produces 19 times the greenhouse gas emissions of trains; and 190 times that of a ship.
* Aviation could contribute 15 per cent of greenhouse gases each year if unchecked.
* Greenhouse gas emissions caused by UK air travel have doubled in the past 13 years, from 20.1m tons in 1990 to 39.5m tons in 2004.
* During the same period emissions from UK cars rose by 8m tons, to 67.8m tons.
* One return flight to Florida produces the equivalent CO2 of a year's average motoring.
* Emissions at altitude have 2.7 times the environmental impact of those on the ground.
* Air travel is growing at UK airports at an average of 4.25 per cent. In 1970, 32 million flew from UK airports; in 2002, 189 million. By 2030 some 500 million passengers may pass through UK airports.
* Cargo transportation is growing by 7 per cent a year. In 1970, 580,000 tons of freight were moved by plane; in 2002, 2.2 million tons. It is forecast to reach 5 million tons in 2010.
* 50 per cent of the UK population flew at least once in 2001.
* Flying 1kg of asparagus from California to the UK uses 900 times more energy than the home-grown equivalent.
full story from Michael McCarthy, Marie Woolf and Michael Harrison here