Airlines are now adding a new tier called "basic economy," in addition to coach and first class, and these cheaper fares come with significant restrictions.
"It might seem like you're saving money, but if you travel with a carry-on bag like this one, you might not be able to bring it on the plane. A basic economy fare puts you in one of the last boarding groups, and if the overhead storage bins are full, you might have to shell out 50 bucks to check it," says Amanda Norcross from AirfareWatchdog.com.
Another big tradeoff: you can't choose a seat assignment or pay for upgrades, such as a seat with extra leg room.
"The best thing you can do is pack light and maybe expect to sit next to the bathroom," Norcross points out.
Meanwhile, more airlines are utilizing a new strategy called "dynamic pricing," which uses browser and search history, as well as device information, to determine the price of plane tickets.
"It's absolutely legal for airlines to search your browse history search history and determine what they think you'll be willing to spend for a flight," Norcross says.
Experts say you can avoid dynamic pricing by clearing cookies and search history, searching for flights multiple times on different days and devices, and booking in an "incognito" browser.
To get the lowest fares, try booking outside of the busiest travel times, and tracking prices through websites like Google Flights or Airfare Watchdog.