Cheap flights won't be found on Tuesdays, but here's how to save on your trip anyway

Each year, more than 2.5 million passengers take to the domestic and international skies, the FAA notes—and most of them are on the hunt for reasonably priced tickets.

Whether it's a frequent flier, or someone looking to purchase a last-minute trip out of town, conflicting theories abound over the best time to purchase the lowest airfares. Among the most popular are booking passages two months in advance—or even on Tuesday afternoons, if a popular travel myth is to be believed.

For those would-be travelers hitting up travel sites every Tuesday, recent data from airfare-prediction app Hopper suggested that strategy may be overrated at best.

Hopper collects around 15 billion data points everyday—including prices, destinations and flight times. It analyzed 11,000 routes worldwide that had a popularity of at least 1,000 searches per week, and found Tuesdays at midnight were ideal for purchasing cheap tickets. That said, the savings were only applicable with less than 2 percent of routes.

"In the past, there used to be more human intervention where managers could create flash sales, often on Tuesdays and Wednesdays," Patrick Surry, chief data scientist at Hopper, told Bloomberg in a widely circulated interview recently.

However, not only do you have to select the right route at the stroke of midnight for lowest fares, you'll only save about six-percent, or $18 on average for domestic flights, Surry told the publication. "It's not necessarily a big win to wait up until Tuesday at midnight to try and shop for your ticket."

With armies of computers managing airfare prices in response to demand, travel experts say there really is no magic day or hour. As a result, your chance of shopping on a Tuesday when airlines decide to put your route on sale is highly unlikely.

"Logically if there were a magic number, everyone would buy on that day. All those cheap seats would be sold out, or the airlines would say, 'oh, we have high demand, let's raise our prices," said George Hobica, Founder of Airefarewatchdog.com

So how should travelers score the best flight deals? It's tough to come up with a rule of thumb about when to buy tickets when prices are dependent on several variables. Those include specific routes, demand, season, and the day of travel.

Because prices are constantly fluctuating, the window of opportunity for a good price takes perseverance and consistent price comparison. To help remove the guesswork and anguish that may come with purchasing flights, there are several airfare subscriptions and alerts that will notify you when prices drop significantly.

The Hopper app provides travelers with information they need to get the best deals on flights with 95 percent accuracy

Airfare Watchdog recommends following alerts and signing up for email notifications, but travelers should be warned that it takes real work.

"Don't assume that you just have to look at one website. I found low prices on Priceline that were not on Orbit, or Orbit that were not on the airline's website," said Hobica. "Not only do you have to search over a period of time, and know what a good fare is when you see it, but you also have to look at multiple sites."

Hopper's Sully recommended that rather than waiting to buy on a Tuesday, having more flexibility on days you travel and which airports you fly to and from, will save you more money. Almost every major airline has a flexible search option on its website that allows you to see which travel dates will get you the lowest prices.

To search multiple airlines at once, Google Flights, Kayak, and Expedia have calendars that allow users to see if they can save by flying a day or two earlier, or later. During a recent flight search for New York to Dallas, a CNBC reporter received a Google Date Tip that suggested savings of nearly $100, just by moving the departure to the following day.

It bears repeating that there is no magic day to purchase flight tickets. However, Hobica said the cheapest days of the week to fly is Tuesday followed by Wednesday, then Saturday because there is less demand on those days.

Mid-August through mid-December mark the beginning of the airline fall season, typically when school is back in session and demand takes a dive, lowering flight prices, he added. "If you went home for thanksgiving, you probably won't take another vacation from that time until Christmas," said Hobica. In addition, he said Jan. 5 to Feb. 15 often see incredibly low fares.

Another method to save is if the price drops and you booked your ticket within 24-hours, many airline websites will allow you to cancel the ticket free of charge. You can then rebook at the lower rate.