Night flights worst for global warming, say researchers.

(From Yorkshire Post)

Chris Benfield Travellers who worry about their contribution to global warming should avoid flying at night and in the winter, according to a report on research led by Leeds University.

The findings suggest that politicians and aircraft operators could probably make more difference by careful timetabling of flights than by cutting the miles covered.

The research investigated the effect of the "contrails" or condensation trails - what most of us call vapour trails - left by aircraft in certain conditions.

In fact they are made of ice crystals formed from water vapour in the atmosphere, although the hot vapour from the …