Well, they should know. An airline industry group predicted this week that thanks to a global recovery and more demand for air travel, the world’s airlines would report a profit that should cheer the industry.

A renewed surge in demand for air travel is expected this summer, which led an industry body to predict Monday that the world’s airlines would report a combined profit of $2.5 billion this year. Nicola Clark for The New York Times reports that air traffic is growing alongside with economic growth in most regions. [ETF Spotlight on FAA.]

But it won’t be smooth sailing.

The weakness of the recovery in Europe, combined with the effects of a weaker euro and the disruptions caused by the eruption of the volcano in Iceland this spring, may leave European carriers deeply unprofitable until at least 2011.