U.S. airlines carried more passengers in 2011 than they did in 2010, but they brought in less revenue from bag fees. The 17 largest U.S. airlines received $3.36 billion in bag fees in 2011, compared to $3.4 billion in 2010, according to the Department of Transportation. Revenue from bag fees decreased despite the fact that U.S. airlines carried 730 million passengers last year, an increase of 1.3 percent from 2010. Delta Air Lines earned 9.2 percent less from bag fees last year and United Airlines brought in 11.8 percent less revenue. Both of these airlines also offer credit cards where cardholders can receive one free checked bag, which may be part of the reason why passengers paid less in bag fees from the year before. Other possible explanations for the decrease include an increase in elite members, who also receive free bags, and passengers bringing only a carry-on bag.

In related news, several airlines are increasing the size of overhead bins on their aircraft, including United, American, Delta and US Airways. And to help bring in more money, United is charging $100 for a second checked bag on some international flights including flights from the U.S. to Europe, Africa (select countries), India and the Middle East. Previously, United charged $70 for a second checked bag. Delta charges $80 for a second checked bag to Europe if checking in online, $100 at the airport. American Airlines currently charges $60 for a second checked bag to Europe while US Airways charges $70.

Alaska Airlines now charges a checked bag fee of $20 for upgraded (U) first class passengers. Elite status members will continue to be exempt from bag fees but if you use one of your confirmed upgrades for a family member, you will have to pay baggage fees for their flights. You will also have to pay if you use your miles for a flight upgrade and are not Elite.