Airlines are striving to deal with the economic downturn and a decline in demand by expanding their roster of a la carte fees for everything from checking baggage to using a pillow. The fees are a source of frustration to some passengers who complain that the charges are misleading and make it difficult to compare air fares. However, a spokesman for the Air Transport Association says consumers accept a la carte pricing from airlines just as they do many other industries. "Is hotel demand down because hotels charge extra for items in the minibar and Internet connections?" he asks. "What about à la carte at the movies, opera or ballpark?"