Whatever You Do, Don't Buy an Airline Ticket On …

Scott McCartney

Updated Jan. 27, 2011 12:01 a.m. ET

Shoppers looking for the cheapest airfare can learn something from stand-up comedians: It's all about timing.

Ticket prices are highest on weekends, on average, according to online travel agencies, fare trackers and airline pricing executives.

When's the best time to buy? Travel experts have long said Tuesday is when sales are most often in place, which is true. An analysis of domestic fares shows that Wednesday also has good—and occasionally better—ticket prices.

Though prices fluctuate frequently and the ups and downs of airline prices can frustrate and anger consumers, airline pricing actually does follow a cycle during the week. Many sales, in which some seats are discounted by 15% to 25% typically, are launched Monday night. That was true again this week when AirTran Airways launched a sale to all its destinations. Competitors typically match the lower prices Tuesday morning. By Thursday or Friday, many sales have already expired.

Two weeks ago, a Chicago-Atlanta round-trip ticket for April travel dates cost $209 on Tuesday and Wednesday on American and Delta, but then $301 for the next four days. When Tuesday rolled around last week, the fare dropped to $219 at both airlines for the April 8-15 itinerary. By Friday it was up to $307 at both American and Delta. Come Tuesday this week, the fare was down to $229.

Like bread, fares get sort of stale toward the end of the week, said Bob Harrell, a fare consultant who has tracked airline pricing for years.

For this analysis, Mr. Harrell studied all fares filed by airlines over the past 90 days and found Monday was the busiest day for fare changes, followed by Thursday.

When airlines want to push through a fare increase, marking up their basic prices across the board usually by $5 or $10, they often do that on Thursday night, then watch to see if competitors match and if the higher rates stick over the weekend. If competitors balk, prices can be rolled back by Monday morning.

ENLARGE

Airline pricing follows a cycle during the week. Above, a Southwest Airlines plane in flight in September. Getty Images