Frequent-flyer tickets are far from free. Legacy airline travelers must shell out $75 if miles are redeemed without "sufficient notice"—considered three days on Continental and 21 days on Delta; American charges $100 if miles are redeemed for a flight sooner than six days away. And since coupons cannot be redeemed on many airline web sites, the traveler must pay for the convenience of booking through a ticket agent. Reward program fees are difficult to avoid, but booking months in advance can limit the exorbitant add-ons—particularly on high-demand vacation routes like Hawaii.
