With air fares soaring, how can passengers trim ticket costs?

LOS ANGELES, CA - JUNE 17: Hundreds of United Airlines passengers stranded at Los Angeles International Airport wait in line outside and inside the airline's terminal for the computer system to come back up on June 17, 2011 in Los Angeles, California. Passengers were stranded for over three hours at numerous airports across the country after a failure in United Airlines computer system.
Kevork Djansezian/Getty Images

(CBS News) Airlines have raised ticket prices three times this year - that's ON TOP of the 20 percent that they've risen since 2010. And just in time for your summer vacation, air fares are expected to jump another 3 percent.

What is an air traveler to do?

CBS News travel editor Peter Greenberg says it's not rising fuel prices - or even the fear of rising fuel prices - that is pushing fares higher.

"It's about capacity," Greenberg said on CBS This Morning: Saturday." "The airlines are cutting flights, they're cutting routes. And when you have that - meaning fewer planes equals fewer flights equals fewer seats - the law of supply and demand kicks in, and air fares have absolutely nowhere to go but up.

"The second culprit is actually taxes. In some countries like the United Kingdom, that can add more than $100 to $150 to the cost of your ticket every time you leave that country. Those two things combined, plus the usual seasonal increase in fuel prices, is what's driving all of this.

Greenberg said domestic fares are about 19 percent higher this year, and overseas flights more than 22 percent higher. And with the increased demand in summer travel, Greenberg said, "There's no reason to indicate historically at least it's going to go lower; it's going to go higher."

Greenberg was also asked about the prospects of a merger between US Air and American Airlines and what that means for airline customers. While a takeover is a big "if," Greenberg said, "No airline merges with another airline to increase their flights, to increase their routes. It's all about shrinking capacity. If that happens, fares will go up again."

When asked how passengers can cut the costs of flying, Greenberg said booking flights 45 to 60 days in advance normally reduces costs. "But it's not about the time. It's actually about how you structure the route of where you want to go. If you want to go from Los Angeles to Hawaii, that's an expensive ticket. However, you change your routing. It's almost counter-intuitive. How about a ticket that goes Los Angeles to Las Vegas to Hawaii? Or Los Angeles - phoenix Hawaii, that may be a lower fare.

"And it also applies overseas. Instead of going to or through London, where you have those high ticket taxes, go to another European capital and then fly from there."

To watch the entire interview with Peter Greenberg click on the video player above.