For airfare, does the day you buy matter?

Travelers everywhere would like a magic potion to predict the best time to buy an airline ticket to get a good deal at the lowest price.

Although seasoned travel advisers say there is no perfect moment to book an airfare, a recent study by Expedia Inc. and Airlines Reporting Corp. (ARC) suggests that based on thousands of flights in 2016, the lowest average ticket prices were purchased on weekends, especially on Sundays.

Expedia crunched numbers gathered by ARC from corporate travel companies and online and brick-and-mortar travel agencies and determined that flights within the United States booked on Sunday were 11 percent cheaper.

Flights from the United States to Europe were 16 percent cheaper, and between this country and Asia, fares purchased on Sunday cost 10 percent less.

'One reason that you are going to see average ticket price on Saturday and Sunday being so much lower is because of the type of travel that is purchased,” said Chuck Thackston, ARC's managing director of enterprise information.

Most travel purchased on the weekends is for holiday or leisure travel, while more 'premium” or business travel is booked during the week.

'Business travelers booking at the last minute, those fares will typically be higher,” Thackston said. 'Airlines are aware that leisure travelers are looking on the weekends, so they'll make those fares available on the weekend.”

Others say the picture is more complicated. Prices constantly fluctuate, based on how full the plane is, the route - and competition on the route - the date of travel, and day of the week.

'I've seen no rhyme or reason to the fare sales,” said Jeffrey Erlbaum, president of ETA Travel in suburban Philadelphia. 'A fare between two points can go on sale any time, but if availability on the flight you want isn't there - if the flight is full - that's going to make a difference.”