Even when buying airline tickets, timing is everything.

Passengers can get the lowest airfares if they buy six weeks before their flight, according to a study by the Airlines Reporting Corp., an Arlington, Va., company that handles ticketing transactions between the nation’s airlines and travel agents.

The study looked at millions of transactions for airline tickets over the last four years and found that passengers pay the lowest price, nearly 6% below the overall average fare, if they buy six weeks before their flight.

The study also showed that ticket prices begin to soar dramatically about a week before the day of travel, and can rise nearly 40% above the average price if passengers buy the ticket on the day of the flight.

“We’re not advising people to purchase tickets only at this time during the cycle as there is no guarantee they will receive the lowest price of the year,” said Chuck Thackston, managing director of data and analytics for the firm. “It is just that the data indicates we have seen this pattern over the last four years.”

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