A new TravelNerd study says that at least 36 airline fees went up last year and "16 others were redefined, bundled or unbundled with other services," this feature says. According to the research, the average increases were $5 to $10. "Travelers really have to be extra cautious when booking a flight," said Alicia Jao, vice president of travel media at TravelNerd. "U.S. carriers are becoming creative at charging consumers extra fees."