The average European flight is getting longer and heavier, according to the region’s network manager, Eurocontrol. That's bad news for an aviation industry keen to lower its carbon footprint by steadily cutting fuel use. Eurocontrol data released Jul. 31 shows how a marked shift from short regional and domestic flights to more long-haul international journeys risks undoing some of the huge gains in aircraft fuel efficiency. Eurocontrol warned Europe’s congested airspace was also hampering its efforts to enable aircraft to fly at optimum altitudes.