Upgrades from discounted economy class seats to business and first class seats will cost $50 plus 15,000 frequent flier miles, the airline said. The increase begins Oct. 1, the Dallas Morning News reported.

"The disparity between discount and premium tickets is too great to be offset by miles alone," said American spokeswoman Marcy Letourneau, who blamed rising fuel costs for the change.

Fuel costs, recently rising from around 25 percent of an airline's costs, have grown to 40 percent of operating expenses in recent months, the News reported.

Airlines have reacted with a slew of new charges.

Delta Air Lines Inc (NYSE:DAL), raised fees for a second checked bag to $50 earlier this week. JetBlue Airways Corp. (NASDAQ:JBLU) said passengers would soon pay $7 for blankets and pillows it used to distribute as complimentary.

"At some point, it becomes like a Saturday Night Live skit, where you're paying for a seat belt and to use the bathroom," Timothy Sieber, an aviation consultant for the Boyd Group told the newspaper.