When is the best time to buy a plane ticket?

Back in February, I read this ‘ask me anything’ on Reddit. Reddit users group-interviewed a former airline pricing analyst, asking questions about fares, overselling and luggage. This answer, about when to book a flight, particularly interested me:

Generally, months in advance. About five months from departure we get an idea of how flights are filling, so we might launch a promotion for sales (say) 6 to 8 weeks prior to departure, which is lower than the ‘default’ lowest fare. Unless you can buy standby tickets, tickets bought late will almost certainly be the most expensive bought for that flight.

We had plans to fly back to Vancouver from France in June, so I decided I’d try to track a couple of flights to see how their pricing behaved. I’m aware that there are sites like SkyScanner that do this automatically, but I had the foolish notion to do it myself.

I picked two departure dates in May, and tracked two flights–the from Air Canada and one from Lufthansa–for each date. I checked the price of the flights every other day. These are the results (click to enlarge)

Here’s the spreadsheet I used to track the prices.

This is strictly anecdotal, of course, and I didn’t faff about with clearing cookies and such. I don’t pretend that there’s much here that we can apply to buying future tickets.

I was surprised to learn that you could have bought the May 7 Air Canada flight the day before you left for just $50 more than if you’d bought it three months earlier. I’d assumed that flight prices generally trended upward as they approached the departure date. Evidently, that’s not always the case.