Otherwise, bank on extravagance. Order tickets for a play, concert, or sports event by phone. Then pick them up that night at the Will Call window. A phone card. This makes an offbeat gift for elderly aunts, kids in college, or anyone conducting a long-distance romance.
Most airports have vending machines that sell the cards.
Fragrance or personal care products. It's easy to find department-store quality. Also, The Body Shop is at many airports. This choice should be reserved for sports enthusiasts, or when special trademarked logos are fun, such as Disney in Orlando, or casinos in Las Vegas. Call your sister and ask if you can go in on the gift she already bought your mother.