Kayak searches hundreds of websites at one time, turning up the web's best flight deals.
You can also set fare alerts for flights. Choose preferred travel dates to destinations of your choice. Kayak fare alerts can be scheduled as daily, weekly or monthly emails.
Kayak's interface also lays out airfare to a particular place across a span of a month or more. Travelers can then pinpoint the lowest rates and the cheapest dates to fly. The company also offers exclusive deals from "Secret Carriers" — airlines are revealed after purchase. Kayak's money-saving management tools also include price alerts.
Yapta is an online tool that helps travelers keep a close eye on airline prices, before and after ticket purchases.
Flyers can use Yapta — now powered by Kayak — to search for the cheapest flights in the upcoming months.
Yapta's super power lies in its ability to track fare changes after tickets have been purchased. If prices drop, Yapta users can claim an airline refund for the difference directly on the platform.
Most travelers aren't aware of airline refund policies. Some airlines offer a refund with any price drop, while others offer a refund when the price drops below a specified amount.
3. Student Universe
Student travelers can buy discounted flights to destinations all over the world with StudentUniverse.com.
The company works directly with major airlines to push the best deals for students. "We are able to negotiate special fares because airlines can depend on our patented verification technology to make sure that students are the ones benefiting from these reduced fares," the company said in an email.
Only verified students can purchase discount tickets. Passengers save $100, on average, per flight with Student Universe.
Skyscanner is a flight comparison platform that lets travelers display the lowest airfare available in a month or year on a graph, so users can quickly pick the cheapest dates to travel.
One search on Sky Scanner compares offers from 600+ airlines, covering more than 67,000 routes worldwide. Like Kayak, Sky Scanner directs customers to official booking websites without fees.
If you haven't decided where to spend your vacation days, use Sky Scanner's "Search Everywhere" option to see where the cheapest flights are leaving from the airports nearest you.
Cut additional costs by searching for "indirect" routes or by using the "flexible" search tool — to mix and match airlines.
5. STA Travel
Like Student Universe, STA Travel bargains with global airlines to win students exclusive travel deals.
STA Travel Exclusives Tickets are available for students under 26. Tickets from top global airlines are "competitively priced" — plus, dates are flexible after purchase.
STA Travel requires the official International Student Identification Card that's available for $22 per year. The cards are available through the company and other outlets with a current student identification card, class schedule or tuition receipt.
6. Airfare Watchdog
Airfarewatchdog is an airfare alerts tool. The site's "dealhounds" will send you an email alert when ultimate deals are found.
Users can schedule alerts for specific city-to-city routes. Travelers can also set alerts for "Anywhere That's Cheap" from all nearby airports. Amazingly low deals will be emailed to you daily, two to three times weekly or once a week. Airfarewatchdog covers most airlines including Southwest Airlines, and smaller carriers.
Each day, Airfarewatchdog also rounds up the Top 50 Fares available for users.
Momondo is a powerful travel resource that scours more than 700 airfare websites for the best deals.
The company describes itself as "small" and "unbiased," searching low-cost carriers, travel agency websites as well as flight offerings from the largest global airlines.
Since their 2006 launch, the company has built more than 700 robots that scan websites "just like a person would do."
Momondo, based in Copenhagen, has especially great coverage in Europe. There are always flights with smaller, niche carriers available. If you can't find deals to low-key destinations in Asia, Africa and Australia, using Momondo is your best bet.
We also love that users can search for direct or indirect flights to multiple destinations.
Priceline'sName Your Own Price program is great for heavily slashed round-trip tickets to anywhere. Money-saving deals — often up to 50% off — are available with some traveler flexibility.