My previous employer had an aviation analyst who wrote detailed research on airlines.
While reading one of these I came accross the most shocking figure, Eazyjet made GBP 248M in 2011 flew 54.5M passengers, that is GBP 4.50 profit per passenger.
For a real airline, the demand, especially at the front of the aircraft is strongly correlated with the economy, revenues and costs are in multiple currencies and for year to year the oil price can double or halve. From a finance perspective an airline is a commodity, currency macro hedge fund.