Take the Peak-Travel Surcharge, for instance. Never heard of it? You may have already paid it. Holiday and summer fares are notoriously expensive, but they are even higher now that airlines such as American, Continental, Delta, United, and US Airways are adding between $10 (for mid-week summer flights) and $30 (for the Sunday of Thanksgiving weekend) to each leg. Delta was even so bold as to add a $50 surcharge to one-way flights on the day after the Super Bowl. And unlike fees for baggage or blankets, these surcharges are folded into the fare, making them undetectable. "It has become extremely difficult for consumers to effectively compare prices and make informed choices when purchasing a fare," says Banas. "And airlines have been taking advantage of that fact, especially by not disclosing fees appropriately."