Summer travel isn't as easy as it used to be for airlines

Making money in the summer is not as easy as it used to be for airlines.

Airlines have drawn down their schedules in August for a variety of reasons. Some travelers are opting to fly earlier, in June or even May, as schools let out sooner than they used to. Demand for flights to Europe has also been moving from the sweltering, crowded summer to the fall, airline executives have said, especially for travelers with more flexibility, like retirees.

Carriers still make the bulk of their money in the second and third quarters. But as travel demand has shifted, and in some cases customers have become altogether unpredictable, making the third quarter less of a shoo-in moneymaker for airlines.

Change of plans, pricier tickets

Airline planners have been forced to get more surgical with sched