Why do online airfares change moment by moment sometimes?
 

I've been checking airfare to Vegas on aa.com frequently trying to get the best price. Today, for instance, it bounced back and forth from around $269 to around $418. How can it change that many times within a couple of hours?

Is there a "secret" as to the best time of day to check for prices?

There is no secret. It is well known that the fares change on an hourly basis expecially at the last minute. some people might give advise such as check on Mondays. I don't know if that is the best day or why that would be true. A plane load of 250 people will have 250 different prices they payed.

While airlines have many reasons, I think they do it just to torment us - I, too, have seen fares go up and down by as much as 50% in matter of hours within same calendar day.

Because they can.

The airlines have a formula, more secret than the launch codes for nuclear missiles, that determines how many seats to allocate at each price and when to change that amount. If there are not enough seats being sold at a high price, they increase the number of cheaper seats. If the flight is getting fully booked even without offering lower priced seats, then they won't. It's basically that simple. As people (and tour companies) buy seats and/or cancel, the number of cheap seats can vary in just the way you saw. One time I was forced to sit three rows from my wife because I was told the plane was fully booked -- when we took off the plane was 2/3 empty. We all chuckled as the flight attendant said the obvious -- that we could change seating as we wished. Obviously, some company bought a LOT of seats but never was able to put anyone in them.

If there was one seat remaining at $269 and it got sold while you waited to decide, that was your decision to wait.

One point to be aware of is that the airline may only be willing to sell one seat at the lowest price when you check. If you check with one, then go back and ask for two, you may get a higher price.

I would look at Southwest or America West for best prices to Vegas. Another mode is to use Travelocity and their lowest fare search if you have some flexibility on travel days.

While Paul Rabe obviously thinks that there is a simple and rational explanation for this, I can tell you the truth. The airlines are in league with the manufacturers of Tums and Xanax to keep the traveling public in a constant, pill-popping state of anxious uncertainty.

And one more bit of Orwellian truth: if aa.com recognizes that you are "shopping" -- i.e., interested in a given route -- it may well be (as many other airline websites are) programmed to tweak fares upward to induce you to grab a ticket at a higher price for fear of having lost the seat altogether.

Many people try to avoid buying any tickets before midweek, also, since early week fares are often higher.

I'd love to meet the guy who proposed and programmed all the software purchased by airline on-line ticketing departments -- he must be a class A Evil Genius.