JetBlue Airways has raised checked bag fees for many customers for the third time in less than a year, according to CNBC. The airline cited rising fuel and operating costs.

Under the new fees, a first checked bag for economy travelers costs $50 if bought more than 24 hours before departure during a nonpeak period, up from $45. Paying within 24 hours of departure costs $60. During peak periods such as holidays or summer, the fee is $55 if bought more than 24 hours ahead, up from $49, and $70 within 24 hours of departure.

Customers who hold a JetBlue co-branded credit card or elite frequent flyer status are exempt from the fees.

"We're adjusting checked bag fees to help offset rising fuel and operating costs," JetBlue said in a statement. "This helps us keep our base fares competitive while giving customers the choice to pay for a checked bag only if they need one."

CNBC reports that jet fuel, airlines' biggest cost after labor, has roughly doubled this year since the start of the Iran war in February. Jet fuel was priced at $4.44 a gallon on Tuesday for the U.S. Gulf of Mexico, according to the U.S. Energy Information Administration. CNBC also reports that other airlines often follow when one carrier raises fees, and that major U.S. airlines did so earlier this year after JetBlue's previous increase.

The changes were first reported by the Thrifty Traveler blog.