How To: What We Thought We Knew About Saving Money on Airfare Was Wrong

Tuesday has long been considered the best day to save money on a plane ticket. Airlines typically announce new deals on Monday, so by Tuesday, all other airlines have matched their competitor's lowest fares. It's a tip that I learned at a young age from my father and was solidified by countless others who swore by it. Well, it turns out that we were all wrong.

Sunday Is the Best Day to Buy

Airlines Reporting Corporation (ARC), a major information services company that provides analysis on plane ticket transactions, released a study showing that Sunday is in fact the best day to purchase tickets, not Tuesday as previously touted.

Tracking over 100 million round trip ticket purchases made between January 2013 and July 2014, ARC found the following information about domestic flights in the United States:

• The lowest average ticket price of $432 was found on Sunday
• Saturday is a close second, with fares averaging $439
• Tuesday ticket prices averaged $497
• Monday ($503), Thursday ($501), and Friday ($502) are the worst days to buy plane tickets

Now that you know Sunday is the best day to purchase plane tickets, how long before departure should you purchase your ticket? ARC has you covered on that, too.

Buy 57 Days in Advance for Domestic Flights

While the price is relatively the same any time between 50 and 100 days before departure, the lowest average ticket price can be found 57 days before flying out.

Combining the data gathered for the optimal day to purchase and how amount to time prior to departure for booking, buying a ticket on a Sunday 50 to 100 days before leaving will typically save you around $110 based on an overall average price of $495.55.

Even if you don't purchase between 50 and 100 days before, purchasing a ticket on Sunday will save you around $50 on average.

Buy 171 Days in Advance for International Flights

ARC also tracked purchases for international flights, with the departing flight leaving from the United States and arriving at an airport in another country. While Sunday still holds true as the best day to purchase a ticket, the window for that purchase varies somewhat from domestic flights.

• Purchasing a ticket anywhere between 150 and 225 days prior to departure yields the most savings, with a savings of $300 from an average ticket price of $1,368
• The lowest average ticket price is $1,004, which can be found 171 days prior to departure

Tickets purchased on a Sunday, anywhere between 150 and 225 days before departure, average a price of $906.03 (savings of $462).

Planning Ahead: The Best Days to Buy Holiday Plane Tickets

Now that we have the information needed for the best savings on fares, here's a list of the best times to buy tickets for the holidays:

Christmas 2014

• Domestic: Any Sunday from Tuesday, September 16, 2014 to Wednesday, November 5, 2014. Wednesday, October 29, 2014 is 57 days beforehand.
• International: We have already passed the prime purchasing window for international flights (Wednesday, May 14, 2014 to Monday, July 28, 2014), but you should still book on a Sunday if you haven't already.

New Year's Eve 2014

• Domestic: Any Sunday from Monday, September 22, 2014 to Tuesday, November 11, 2014. Tuesday, November 4, 2014 is 57 days beforehand.
• International: We have already passed the prime purchasing window for international flights (Tuesday, May 20, 2014 to Sunday, August 3, 2014), but you should still book on a Sunday if you haven't already.

Thanksgiving 2015

• Domestic: Any Sunday from Tuesday, August 18, 2015 to Wednesday, October 7, 2015. Wednesday, September 30, 2015 is 57 days beforehand.
• International: Any Sunday from Wednesday, April 15, 2015 to Monday, June 29, 2015. Monday, July 8, 2015 is 171 days beforehand.

Christmas 2015

• Domestic: Any Sunday from Wednesday, September 16, 2015 to Thursday, November 5, 2015. Thursday, October 29, 2015 is 57 days beforehand.
• International: Any Sunday from Thursday, May 14, 2015 to Tuesday, July 28, 2015. Tuesday, July 7, 2015 is 171 days beforehand.

New Year's Eve 2015

• Domestic - Any Sunday from Tuesday, September 22, 2015 to Wednesday, November 11, 2015. Wednesday, November 4, 2015 is 57 days beforehand.
• International - Any Sunday from Wednesday, May 20, 2015 to Monday, August 3, 2015. Monday, July 13, 2015 is 171 days beforehand.

For more tips on getting cheaper airfare, check out Gabby's shopping guide for holiday traveling and Yumi's 9 tips for booking cheaper flights. And if you've got some tips of your own, share them below in the comments!