Domestic airfares have been climbing steadily since 2009, and there was no letup last year.

But the uptick in ticket prices was not as steep as in the last few years.

Domestic airfares increased 4.2 percent in 2012 compared with the previous year to an average of $427 per ticket, according to Airlines Reporting Corp., an Arlington, Va., company that completes the financial transactions between 16,000 travel agents and 187 airlines.

The good news is that the fare increases have been shrinking. In 2010, domestic airfares rose nearly 13 percent and climbed 8.5 percent in 2011, according to federal statistics.

But don’t celebrate just yet. The fees that Spirit Airlines of Florida and Allegiant Air of Las Vegas charge to bring carry-on bags into the cabin may be adopted by other major airlines in the next year.

That prediction comes from George Hobica, founder of the travel website Airfarewatchdog, who got the tip from a source at one of the nation’s largest airlines.

Travelers hate airline fees, but Hobica points out that deterring carry-on bags can speed up the time it takes to load and unload passengers.

Hobica predicts that once one of the nation’s larger airlines — United, Delta or American — adopts a carry-on fee, other carriers will follow soon after.

“Don’t see why they wouldn’t do it,” he said.

(c)2013 Los Angeles Times. Distributed by MCT Information Services.