Global Warming leads to longer flights which lead to Global Warming.

Warming Leads to Longer Flights, More Emissions

"“Normally, when we think about the airline industry and climate change, we think about how global aviation contributes to climate change through such means as carbon dioxide and aerosol emissions — and for good reason,”  Karnauskas said. “However, in our study, we’re flipping this around. We’re trying to probe the extent to which climate change might influence the airline industry beginning with shorter-term natural cycles that we can readily observe with existing real-world data.”" 

More here - http://www.climatecentral.org/news/warming-longer-flights-more-emissions-19234