Letters: Transatlantic aviation Sunday Telegraph, p 23, 21 February 2016 SIR - My scientific study into the effects of climate change on transatlantic aviation did not predict that climate change would add "an hour or two" to flight times between Britain and America. While Christopher Booker is correct to point out that the difference in air temperature between the tropics and the poles is decreasing at ground level, it is actually increasing higher up in the atmosphere, at the levels where planes fly. This effect is entirely consistent with our understanding of global warming, but its impact on aviation is only just being explored. Dr Paul Williams University of Reading