1. Nonstop flights are usually cheapest.
There are times where flights with stops are cheaper because the airlines know this takes more time for the passenger and that they will be willing to pay more to fly non-stop, but one-stop flights actually cost the airline more. (They need to fly an additional plane.) Airlines save more money when passengers fly non-stop, so they will often be cheapest.
2. Book around 3 weeks before departure—maybe.
According to data from 2016 and 2017, 2-3 weeks in advance of departure was the cheapest time to buy airfare. However, this data varies a lot: San Francisco was cheapest between 7 and 12 weeks, for example. If you’re really looking for a great deal: look early and often.
3. Stay over on Saturday.
When you stay at your destination through Saturday, you will save more money on your ticket prices, according to studies.
4. And buy tickets on a Sunday.
According to Scott McCartney of the Wall Street Journal, when buying an airline ticket online, the prices can fluctuate wildly from day to day. This means that there is one day that is statistically cheapest to buy a ticket online: Sunday. (However, you can avoid all of this by working with a travel agent, who will find you the lowest fare on first and business class tickets.)
Bonus Tip: Oil prices don’t affect fares anymore, according to studies by Macquarie and ARC/Expedia Group. It used to be that oil prices made up a large part of airline spending, but that’s not the case in 2019. So, there’s no reason not to book your trip when oil prices are high.