We’ve all seen the research, or in many cases, the estimated guesswork, as to the best time to book an airline flight to get the best deal.

The latest data seems to indicate it’s about 15% cheaper to book on Sundays.

For the moment, there are fewer expensive business class fares booked on Sundays.

But what about the day you choose to fly?

The least expensive day to travel is Tuesday. It remains a lighter travel day than Sunday or Monday.

And of course, less demand means there’s more inventory for the airline to try to sell.

That also applies to cashing in those hard-to-redeem frequent flyer miles.