US Airways Group Inc., which next month will begin charging passengers for coffee and sodas, has expanded the number of seats that cost passengers as much as $30 extra to reserve.

About 16 percent of seats in coach are now included in the "choice seats" program, double the 8 percent from its May start. The fee now applies to tickets for seats in the center, along with aisle and window, near the front of the cabin, the Tempe, Ariz.-based carrier said in an employee newsletter.

US Airways is moving to more "a la carte'" pricing, where charges for services or products such as checked luggage or onboard food and drinks are separate from the ticket. The changes are designed to boost revenue and help counter record high fuel prices that are eroding profits.

"Sales have been strong, revenue has been encouraging and refunds and complaints have been very few," US Airways said in the newsletter. The company would not provide specifics yesterday.

The increased or added fees are expected to produce as much as $400 million a year in new revenue, US Airways has said. The carrier declined to break out revenue from the choice seats program, and may expand the program again in the future, said spokesman Morgan Durrant.

Passengers pay between $5 and $30 more for the seats per flight segment, depending on length. US Airways' frequent fliers with Dividend Miles Preferred status don't have to pay the fee, nor do passengers who find no other seats available.

Choice seats are available only when passengers check in online 24 hours before a flight. US Airways will expand the program to ticket counters and kiosks later this year.