Scientists have been arguing about the climate impact of contrails for many years, as the clouds that they form impact both cooling and warming.
Contrails reflect sunlight back into space and cool the Earth but they also trap infrared energy in the atmosphere, adding to warming. Researchers believe that the warming effect is more significant than the cooling.
Now scientists at the University of Reading have tried to work out how this impact could be reduced by altering the flight paths of long and short haul aircraft.
"You think that you have to do some really huge distance to avoid these contrails," lead author Dr Emma Irvine told BBC News.
"But because of the way the Earth curves you can actually have quite small extra distances added onto the flight to avoid some really large contrails."