Beginning on May 5, passengers traveling within the U.S., Canada and parts of the Caribbean who buy nonrefundable domestic economy tickets and aren't Premier-status or higher members of United's frequent-flier program, will be charged $25 to check a second piece of luggage.  

The move by the world’s second largest carrier is in response to rising fuel prices which have jumped 50% in the last year. With the new baggage policy, United expects to generate some $100 million in savings and new revenue, according to a Bloomberg news report.  

Though no other major U.S. carriers have announced plans to create similar policies, the additional baggage fee arrangement is already in place with smaller carriers like Virgin America, which charges $10 for a second checked bag. Similarly, low fare carrier, Southwest Airlines began assessing a $25 charge for a third checked bag beginning on January 29, while some popular European discount airlines like Ryanair charge to check all bags.  

United also changed its baggage policy for all customers. Effective immediately, the cost to check as many as four additional bags will be a flat $100 each rather than staggered between $85 and $125 per bag as it was previously, according to an airline statement.