In 2013 U.S.-based airlines raked in more than $6 billion from baggage and change fees, but that’s not stopping them from upping their fees again in 2014.

United Continental Holdings Inc. (NYSE:UAL) has doubled its fees for oversized bags, with a $200 fee coming into effect on Dec. 13. In addition, the nation’s second-largest airline has upped its fee for carrying three or more bags from $100 to $125 each. A United Spokesperson said in an email to Bloomberg that the reason was because of the complex and costly infrastructure needed to deal with oversized bags. So it's no surprise that United has taken in nearly $650 million in checked baggage fees in 2013, not far behind first-place Delta Air Lines Inc. (NYSE:DAL), with around $1 billion in fees collected in 2013.

On the other hand, Spirit Airlines Inc. (NASDAQ:SAVE) has increased its meager baggage fees from $5 to $6 for people who pay during online check-in and $10 to $15 if purchased through the reservation center. However, Spirit will still charge $100 at the boarding gate for all carry-on bags and each bag that has to be checked in after booking. 

On the other side of the Atlantic, Virgin Atlantic will charge $41 (25 pounds) each way to passengers who choose a seat less than 24 hours before departure on long-haul flights, a symptom of being partially owned (49 percent) by Delta.