GOOD DAY FOR: Booking that flight, after American Airlines said it will add new nonrefundable fees for its frequent-flier program and up the mileage requirements for upgrades and free tickets, effective Oct. 1. Delta also upped its mileage fees and requirements last week. “The increase in fuel has an impact on everything we do right now,” says American spokeswoman Marcy Letourneau. (The New York Times)

BAD DAY FOR: Freewheeling, after high gas prices are prompting Airstreamers—retirees and other enthusiasts who pull Airstream RVs across the country—to stay home, stay put, or come up with other ways of cutting fuel expenses. Airstreamers Karen Catchpole and Eric Mohl, both 42, suggest using cruise control and finding the most direct route through GPS mapping. (MarketWatch)