United Airlines has raised their fares by $10 round-trip on most of their domestic routes, according to USA Today. This is the eighth attempt by airlines to raise fares this year.

The fare increase applies to routes in all states except Alaska and Hawaii, according to Charles Hobart, a spokesman for United Airlines.

Of the previous eight attempts to raise fares, only two have been successful, and both of those were led by Delta Airlines, according to FareCompare.com, a web site that tracks air fare.

Fare increases generally only stick if low-cost carriers such as Southwest Airlines participate. Currently, neither Southwest nor other major carriers have matched United's increase.

The fare increase is the third attempt this year for United Airlines. Delta has tried to increase fares five times.

Last year, airlines tried to boost fares 15 times, though they only had success seven times. The increases were despite the fact that the airlines had a profitable year. The argument they provided was that higher operating expenses, especially for jet fuel, required higher airfare.

Airlines have not been as determined to raise prices this year, Rick Seany, the CEO of FareCompare.com, said. Delta Airlines made the last attempt on April 22. It didn't work out.

Airlines were more aggressive about fare hikes last year because the economy was stronger, Seaney says. This year, economic and political issues both domestically and internationally have made them less determined to push through higher fares.

Automatic budget cuts caused by the sequester in Washington, D.C. have been among the reasons airlines aren't pushing so hard. Oil prices have risen due to the unrest in Egypt, which also presents a problem.

"Certainly, that has to be worrisome," Seaney said.

United is waiting for a match from Southwest so their price increase will stick.

"They're probing for two things: the appetite for their competition to raise prices and the appetite of consumers to continue to fly them at higher prices," he said. "You can't hang out there above market rates for very long."

Seaney believes consumers are less willing to pay higher fares this year.

"I think consumers are telling airlines, 'Look, I don't have that much money in my wallet," he continued. "'If you give me a choice between higher prices and not going, I'm not going.'"