Buy airline tickets on Tuesdays? Save with long layovers? There are plenty of strategies for saving money on airfares. But when researchers dug through global airline-ticket price data, they discovered that the conventional wisdom often was wrong. 

Myth: Airline tickets are cheapest when booked on Tuesdays. Reality: Sunday is savings day for buying tickets, with prices typically 20% below average. Prices generally are highest on Thursdays and Fridays. Weekends are the secret to cheaper airfares in another way as well—on average, you’ll save around 25% if you set departure and return dates so that your trip includes a Saturday night stay. That’s because leisure travelers often won’t pay as much as business travelers—and leisure travelers are far more likely than business travelers to book travel that includes a Saturday stay.

Myth: You get the best prices if you wait for last-minute travel deals. Last-minute deals do appear occasionally, but waiting to snag them is a losing gamble. Three weeks before the travel date tends to be the sweet spot—you’ll pay 28% less on average than you would within five days of departure. If you’re heading to a popular beach or ski destination at peak season, the lowest ticket prices tend to appear earlier—typically six weeks before the travel date.

Myth: Flights with transfers inevitably cost less than nonstops. Reality: Nonstops now are the least expensive option for around one-third of flights where direct routes are offered. Nonstops are particularly likely to be cheapest with newly added routes…routes to out-of-season destinations…and on weekend trips to destinations mainly visited by business travelers. 

Myth: Ticket prices spike when oil prices spike. Reality: Oil price increases generally do not push up ticket prices in the short term. Airlines have lengthy jet fuel contracts that shield them from week-to-week oil-price fluctuations. When oil prices remain high for many months or years, that can increase ticket prices, however. Counterintuitively, that means that if you’re planning to take a trip, it can be a good idea to buy tickets soon after oil prices spike. The spike probably didn’t drive up prices, but if you wait and oil prices remain high, tickets might indeed become more expensive.