You may want to take a deep breath before reading this one: Airlines collected a whopping $3.4 billion in baggage fees last year, up 24% from 2009. Reservation and change fees accounted for an additional $2.3 billion, down 3% from the year prior. The add-ons are one of the few bright spots for an industry that is caught between rising fuel costs and customers who expect rock-bottom airfares. Analysts say without the fees, the industry would be losing money. (More airline industry stories.)