When planning a vacation, the less you spend on flights, the more you can put toward exploring your destination.
The ideal time for domestic flights: 70 days in advance. That's within what CheapAir.com calls the "prime booking window," which stretches from 21 to 121 days early to lock in the best prices. "Fares bounce around but frequently are available for within 5 percent of the lowest price," the study says.
The time of year you're aiming for matters as well. Here's how far out is ideal for each season:
Range: 14 to 160 days in advance
Best fare: 47 days in advance
Range: 21 to 100 days in advance
Best fare: 69 days in advance
Range: 21 to 110 days in advance
Best fare: 62 days in advance
Range: 46 to 122 days in advance
Best fare: 90 days in advance
For travelers wary of cutting it too close to their vacation, CheapAir.com says booking slightly earlier, 122 to 168 days in advance, will still offer plenty of good deals, but it will you cost an average of $20 more.
And while it's cheaper to fly out on a certain day, it makes no difference when you book your tickets, the study found.
It's also worth noting, though, that fares for individual trips are volatile, so it's best to keep an eye on the prices and jump on deals whenever you see them.
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