Flying is nerve-wracking and expensive for many people. Yet, many don’t think about looking for ways to save money on their flights. You can save hundreds of dollars per flight if you know where to look. The only question is how to pick the right site to help you in your search.

These sites have been compiled based on the criteria of saving you time, money and frustration. Most hook into the major air carriers in order to find the best deals. Some include search filters to allow you to dial in what you’re looking for. You can pick the type of plane, route, fare class, and much more. There’s also a important drawback on some known as “Opaque bookings.” This means that you don’t always know the time or even the airline you’ll be using until the after the purchase. Many people dislike this lack of flexibility and uncertainty. It is simply part of what allows most sites to offer money-saving deals since they are buying leftover deals. Look out for booking fees too, they can ruin your savings. This guide has five solid sites since none are always perfect.

1. Momondo

This site has been shown to be 95% cheaper than all other travel sites in studies. Momondo pulls in results from over 1000 airlines, booking sites, search engines and travel agencies. It has a lot of functionality like how a simple search shows you the cheapest days to fly. You can see the seats, class, fares and even a user rating. There is another feature called the “Trip Finder.” It shows you trip ideas and the best times to visit the location. You’ll even see the prices and the weather forecasts.

The catch is Momondo isn’t a booking site. It only brings you directly to the site with the best deal. Other sites are all-in-one packages, so this shouldn’t be a big deal. Momondo may also take some time to load. It compensates by being one of the powerful deal-searching services.

2. Hopper

Many people don’t know about Hopper. It’s an app for your phone with a very simple user interface. The company says you can save up to 40% on your flights when using their app. It does this by receiving secret fares from its partnered airlines. The color coded map is another plus. Many users also like being able to set alerts one month in advance. This helps save money for those who don’t have to fly on a specific date.

The main issue is you can only use Hopper with your smartphone. Just remember that it is very easy to use. It offers a great deal of flexibility and low prices.

3. Expedia

This is one of the first OTA sites that most people think of. It is one of the first to exist in the industry. It is a reliable site that works like most others. Sometimes the deals are not always the best value. Another drawback is that you might not be able to upgrade your flights if you use this platform. You should simply look at it as another option in your toolkit. Expedia makes up for this by offering you reward points to five you better discounts on their platform.

4. Hotwire

Many people turn to Hotwire to save the hassle of shopping around. It is a popular OTA that has been in business more than 20 years. Their homepage is simple to use. You just enter your desired arrival and departure times and the day you wish to travel. Click the third tab to perform the flight search.

Another bonus is that you can find great deals by bundling your hotel and flight. There will be plenty of side offers for hotels while shopping. This includes the option to pick the hotel’s star rating and its "Trip Advisor" rate to help you find the best place to spend the night. You’ll find that this often gives the best overall value. Make sure you look out for the booking fees at closing time. There is also a 24 hour cancellation policy and their “Low Price Guarantee.”

5. Kayak

This is a popular travel search engine. You should start most of your searches on this site. It pulls data from a number of major travel sites and airliners. This site gives you many different settings to filter your searches. You might be surprised how specifically you can narrow down the available flights. Then, you can directly visit the site you’ve clicked on.

There’s a great feature known as the “Kayak hacker fares.” It helps you bundle round trips on different airlines to save time and money. Many other sites don’t show these kinds of deals. You can even track the prices with price alerts.