One thing that makes me laugh out loud, is reading various travel pundit's advice on "when to buy the cheapest flights" because online website analysis and the examination of various bookings made, shows that the best time to buy a flight ticket is.... Yes! On a Tuesday afternoon at 3.07 pm, but only after having walked twice around a thorn bush and having laid a small piece of three day old cheese on the front door step of a hermit like person who lives in your street, at number 36... or something.
CheapAir recently decided this was the best time to buy, from their research which covered "... 350 million airfares between the US and over 3,000 markets". Conde Nast Traveler and even CNN picked up on stories with regard to mythical "sweet spots" for buying air tickets. Skyscanner have come up with a magic app which will produce the best flights for you and multiple travel writers in general, have waxed long and lyrical as to how they had found the air travel booking holy grail.
All of the above is, of course, on balance, well..... rubbish.
Air travel is a very personal thing. We are not about 350 million airfares or 3000 destinations. We are about you and/ or yours, travelling from a specific point on the planet, to another specific point on the planet for your reasons on your dates (or at least, within a specific time frame). If your friend's wedding is in Barcelona and that wedding is on the 12th July, there is little point rocking up on the 25th July in Seattle. If your school is having a reunion on the 14th October in Kansas City, finding a cheap flight to Rome for the 16th November would be, naturally, great, but useless. If your Aunt suggests you come over to Phoenix "....around the first two weeks in March", true, you have a bit of leeway but still, that April flight to New York somehow, just won't cut it.
There is no real mystique: a lot of airline pricing is common sense. Going anywhere for a major public holiday will cost - schedules are loaded some 11 months in advance, so if you wish to travel during a public holiday, you need to be that far ahead. Even then, airlines know that flights for that period will be busy, so very often, the cheapest seats are not made available. Airlines have seasons. Peak seasons for any destination, are governed by how many people wish to fly. So, during the summer months, there are no cheap flights to major holiday destinations - want a super-cheap seat to the Caribbean? Try the hurricane season.
In the winter months or where there are no holidays to speak of and people are working, then the front of any aircraft is generally busy and the back, empty. Come holiday season (when any cynic would say that people have to pay for flights from their own pockets) then the back is full and the front empty. Very often, special offers may be had on upgrades during these periods; but don't expect to find discounted seats available for, say, London to Singapore in business class, during October.
A flight is a highly perishable product and for many years, now - long before many online websites were even a twinkle in a venture capitalists' eye - airlines have monitored bookings for any given flight, almost on an instantaneous basis. As a flight fills, then cheaper priced seats are removed, as the date moves closer, some cheaper seats may be re-introduced. Ah! I hear you cry.... so there may be a "sweet spot". There may be on a rather desultory schedule to a few destinations - in the same way that your lottery numbers may come up next Friday, the price may go down by $10 on a $300 fare. On the other hand, it may go up by $50 - if you wish to leave it on the off-chance... Well, good luck with that.
So, when is the best time to buy? There is a simple rule: If you have to go to a specific destination for specific dates/ times - book as early as possible. If you don't mind where you go and when - book as late as possible. The most important factor is if you are comfortable with whatever fare is offered and that the flight gets you where you need to be, when you need to be there.
If someone sitting beside you paid $20 or $30 less and takes great delight in explaining why you should have booked ten nanoseconds before the gate closed....okay, but then again, perhaps they are not attending, what is for you, a very important job interview or meeting.