Airlines are cutting back on routes and offering fewer flying plans, as well as fewer staff members on the front lines. They are focusing more on their higher-margin customers—business travelers—and less on families, traditionally their lowest-paying customers, says Kyle McCarthy, editor of the Family Travel Forum (www.familytravelforum.com).

Fees for services that once were part of the ticket price, such as selecting your seats in advance, mean that, in some instances families are paying more in order to sit together. Then there are those baggage fees, which can add up for a family traveling. And some benefits, such as early boarding privileges for families traveling with small children, are becoming less common.