Delta Air Lines is doubling its fee for checking a second bag to $50 for domestic flights, or $100 for a round-trip domestic flight.

[ Post your comments below. ]

The new fee goes into effect for customers who buy tickets July 31 or later, for travel Aug. 5 or later.

Atlanta-based Delta is also increasing its fees for additional bags, overweight bags, oversized bags and items that require special handling, like ski equipment.

Delta did not announce a fee for checking a first bag, as other airlines have.

"At this time we believe that the first checked bag is part of the service provided associated with the price of a ticket," Delta spokesman Kent Landers said. "But we will continue to evaluate everything given the fuel environment."

Delta said fewer than 20 percent of its customers check a second bag.

Travelers on international Delta flights will still be able to check two bags for free and first class, BusinessElite and Medallion passengers on Delta will still be able to check three bags for free.