My two favorite travel websites for finding good airfares are: Skyscanner when I’m traveling on specific dates and Google Flights when my travel dates are flexible.
Skyskanner: Search by dates
Use Skyskanner to learn how airfares change over time. Set an alert for your route and dates, and you’ll be notified by email every time the airfare changes. Once you see what the usual price is, you’ll be able to tell when fares are too high or are below “normal.” The farther out you are from your trip, the more you can learn the system. I usually find the best deals within six to eight weeks before I want to travel. Be patient, and don’t buy too soon.
I recently used this site to find a $499 RT non-stop flight from Seattle to Frankfurt on Lufthansa. I hadn’t seen it that low in…ever, so I bought it immediately! Skyscanner provides checkboxes to select a variety of travel sites to search.
Google Flights: Search by deals
Use Google Flights when you have a flexible itinerary. Enter your departure city and arrival city. Click on the calendar icon in the date box, and select “flexible dates” to see prices for all upcoming dates. You can scroll week by week or month by month. Google Flights has a very basic interface, but I like that it gives me a good visual of what time of year prices are lower and on which days it’s cheaper to fly.
I use this site when I have a destination in mind and want to find the cheapest time to travel.