The New Way Some Airlines Are Pricing Tickets, Under the Radar

— -- For years, booking a one-way ticket was the most expensive option when it came to airline travel, but now some of the country's largest airlines are changing the way they price their multi-city fares –- and so far it's been pretty hush-hush.

"The airlines are actually charging you more if you try and buy one ticket that stops in multiple cities," said Scott Mayerowitz, an airline expert with the Associated Press. "It can be hundreds of dollars extra than buying individual itineraries separately. ... It used to be the multi-city [fare] was the way to go. Today, one-way trips are much cheaper."

Mayerowitz said that major airlines like American, Delta and United had been making this change in the last few weeks and that most consumers didn’t even know about it. And, he said consumers could be missing a chance to save anywhere from a few hundred dollars to up to $1,000 for a single itinerary.

"Before booking any ticket, travelers should go ahead and price out one-way itineraries for each leg for the trip. It might be a bit more of a headache but you can save hundreds of dollars by doing so," he said.

Airlines had been trying to compete with low-cost carriers by offering incredibly low prices on select flights, according to Mayerowitz. The airlines then got wind of the fact that some travelers were buying up those one-way flights and creating multi-city trips for cheap. So the airlines made some changes.

According to the AP, Joshua Freed of American said that the airline had "made some changes because of customer feedback and are watching it closely." Delta had not commented on the reported changes and United's comment was similar to American's, the AP reported.

If you've got the post-spring break traveling itch and have your eyes set on hitting the friendly skies this summer, experts are suggesting you act soon.

"Travelers this summer could see extremely low airfares if you're savvy enough to search around and search for one-way flights. ... These low prices are going to last probably for several months. ... As long as you're searching one-way segments, you'll find the best deal out there," Mayerowitz said.

ABC News' Rebecca Jarvis and Kelley Robinson contributed to this report.