Thank fee-happy airlines for that— there's no limit to what they'll charge for, from meals to checked bags and flimsy pillows.
According to the U.S. Bureau of Transportation Statistics, airlines made $3.3 billion in baggage fees alone in 2011.
With summer travel season in full swing, we've rounded up the best money-saving tips out there.
Test the 24-hour rule
After you book, check the next morning to see if the price of your airfare fell.
If it did, give the airline a call to cancel your flight and often you can rebook without penalty.
Take last-minute trips
Airlines are known to cut prices when they can't fill planes for an upcoming weekend trip.
On Tuesday, they'll email offers for the coming weekend or following one to fliers who signed up for alerts. Travelers can leave Friday night or anytime Saturday, then return on Monday or Tuesday.
Chase the fare, not the destination
Kayak's explore tool (kayak.com/explore) is useful for searching multiple airline fares at a time.
You'll instantly see a map with all the destinations listed under a set budget.
Leave on a Wednesday
It's the cheapest day to do it, saysFareCompare.com, especially for domestic travel.
Per the website: "The day with the most seats is likely to have better supply, and thus ... more empty seats that require discounting to fill the plane—meaning they'll have to release more seats at their cheapest price point."
Book on Tuesday at 3 p.m. Eastern Time
A study byFarecompare.comfound this was the best time to buy airline tickets and shop for domestic travel.
Check Twitter and Facebook
Airlines have been experimenting with blasting fares via social media, especially Jet Blue, reports the AP. But you have to be fast: Some deals can be gone within hours.
"If you find something, jump on it," says John DiScala, who travels frequently and writes baout it at JohnnyJet.com.
Some airlines announce special sales to Facebook fans as well.
Fly two different airlines
Sometimes it's worth it to mix and match. Most airlines now sell one-way flights at reasonable prices, meaning one might be cheaper for the outbound flight while the other works better for the return.
You could even fly to one airport and depart from another.
Become a frequent flier
It pays to cozy up to your airline of choice.
Become an elite member of the airline's frequent-flier program or use a credit card that's tied to the airline to get a leg up on other travelers, says U.S. News' Daniel Bortz.
Likewise, if you're using a credit card that offers rewards, check to see if those rewards can be redeemed for miles or travel gift cards, suggests Ask Mr. Credit Card.
Sign up for free alerts from AirfareWatchdog.com
With this site, you'll get pinged when prices fall and receive some excellent deals. The site uses real people to vet the deals rather than computers, so you're bound to turn up some offerings you wouldn't have found otherwise.
Says founder George Hobia: "We only send updates when we think we've found a good deal, whereas other sites might update you when a flight drops $2."