This past week, Delta Air Lines announced changes to their frequent flyer program, Delta SkyMiles. The changes, which include rewarding travelers based on the amount of money they spend on tickets rather than simply on how far they fly, raised questions about the evolution of loyalty programs in the airlines industry. Goizueta marketing Professor Michael Lewis conducts extensive research on loyalty programs and consumer behavior. He spoke with us to offer his perspective on the shift in reward programs and who it ultimately benefits.