(Reuters) - United Continental Holdings Inc UAL.N on Friday increased its checked bag fees on routes to and from North America, the Caribbean and Central America, the company said, as it grapples with rising fuel costs.

FILE PHOTO: A United Airlines aircraft taxis as another lands at San Francisco International Airport, San Francisco, California, U.S., February 7, 2015. REUTERS/Louis Nastro/File Photo

The parent company of the No.3 U.S. airline will now charge $30 for the first checked bag on the routes, up from $25 previously.

The company said that charges for the second checked bags within the United States, Puerto Rico, Virgin Islands, Caribbean and Central America will now increase by $5 to $40.

“We are making adjustments to our checked bag fees in select markets - most of which have not been changed for the past eight years,” United said in a statement.

Rising costs have been a concern for airlines, as high fuel prices and bumps in salaries and benefits for pilots, flight attendants and mechanics have swelled operating expenses.

Smaller rival JetBlue Airways Corp JBLU.O on Monday also increased the fee on the first checked bag by $5 to $30, and on the second checked bag by the same amount to $40 on all routes. (bit.ly/2LIY6zR)

But not all airlines have yet taken to charging increased fee for ancillary services, partly due to competitive pressures.

No.1 U.S. airline American Airlines Group Inc AAL.O will allow basic economy class travelers to bring a full-size carry-on bag free of charge, starting Sept. 5.

“The carry-on bag restriction left us uncompetitive from a product attribute perspective in some markets,” American Airlines President Robert Isom said on a post-earnings call in July.

Southwest Airlines Co LUV.N, the No.4 U.S. airline, said on Friday it would continue to allow passengers to check two bags and change their reservation without the worry of additional fees.

“Customers come with luggage, it’s a part of our business, and Southwest doesn’t believe in charging punitive fees for bringing along necessities for travel,” Southwest spokeswoman Brandy King said in a statement.