Here’s when passengers will pay the least for flights this fall, experts say — and the savings start next week

Back to school? More like back in the saddle.

September means summer’s ending, but savvy travelers know the coming month is also is the beginning of shoulder season — that quietly magical moment when travel becomes more affordable, destinations can be less crowded, the skies a little friendlier again.

But, according to Expedia, there are times within the upcoming season where the deals are really at their best — the week of September 1 for example, experts at the third-party booking site revealed in a new fall travel report.

During that entire week, airfares are averaging $100 down from the peak of summer, as many of the travelers crowding global airports just weeks ago are suddenly grounded by work and school schedules.

Those lucky enough to have the freedom to move can clean up, deals-wise. And if you are interested in international travel, the week of Oct. 20 will bring average overseas fares down by a whopping $260 a pop from summer’s worst, the pros stated.

Looking for total quiet? The week of November 10th — during the ever-predictable, pre-Thanksgiving lull — should be deathly still in many destinations.

So will pretty much every Monday during the season, the number crunchers nudged, suggesting that to save big, travel on the first weekday above all others. That could save you about 15% on a domestic flight. Saturdays were the runner up for cabin elbow room — and savings.

And where to go? Spots like Tulum, Mexico, Mallorca, Spain and Tokyo — the latter boasting a surprisingly favorable exchange rate right now — are trending, the site said.

And last but not least on the hot list, there’s Indianapolis, where interest is up a whopping 120%, but there’s reportedly a reason for that — Taylor Swift’s “Eras Tour” is stopping by in November.

If getting a lot of bang for your buck is more important than where your affordable flight lands, there are three destinations that US travelers should be keeping an eye on, the site said — give some thought to Las Vegas, Cancun and Paris, presumably taking it rather easy after spending a hectic summer in the spotlight.

Also keep an eye on Honolulu, Seattle, London and Dublin, Expedia urged — all are seeing a 15% or more drop in average airfares in the coming weeks.

“Regardless of the destination, fall is a fantastic time to travel and there’s still time to plan a getaway,” Melanie Fish, head of Expedia Group Brands public relations said in a release.

“The week following Labor Day is the best time for domestic airfare deals, while Oct. 20 is the best for international trips — and for the start of leaf-peeping season.”