This article may NOT contain the answer you are looking for, but I do hope it clears up some of the confusion and misinformation that is floating out in cyberspace when it comes to the best days and times to buy airfare for your upcoming dream vacation.
First, here is a fact about airfare prices, they fluctuate on almost a minute by minute basis. The fluctuation is due to computer algorithms that set prices based on the number of seats still available on a certain flight. As seats sell, prices change. Its good ole supply and demand, plain and simple. There are a lot of detailed articles out there trying to give more detail into why prices are so different for the same flight on any given day, but it all boils down to economics. If a flight is a popular route, you can count on the fact that prices will reflect it (i.e. supply and demand) and that won't matter if it is on a Monday, Tuesday, Wednesday etc.
Second, we get asked all the time whether it is cheaper to fly on a Tuesday vs a Friday etc. The answer still goes back to supply and demand. It very well may be cheaper because a lot of business travelers leave out on Sundays and Mondays and come back on Fridays or Saturdays. But keep in mind that airlines know this and the number of flights reflect the busier days and routes which brings up the issue of availability and the number of connections.
Third, what you see when it comes to the published fare may not be the real cost of flight. For example, you bought a ticket on "ABC Airlines." Then when you went to choose your seat, the only available seat for the price was a middle seat near the back bathroom. So you see that the seat is in an awful location but you also see there are other seats that you can upgrade to for the everyday low price of $60. So you waited until Tuesday to buy that airfare that was $30 lower but ended up paying $60 more for a seat you actually want to sit in.
So with all of this said, here are the factors that should play into your decision of when you want to buy your airfare:
1) How committed are you to the trip? If your trip dates are set due to vacation schedules and you are set to a certain departure and return date, you should consider buying your airfare as soon as you can. I say that because if your vacation destination is a popular one, the good flights (good times and connections) can sell out while you wait to see if the fare is going to drop $20 to $50.
2) Single vs multiple connection flights. Let's assume there are no direct flights between where you are and your destination so you will have at least one connection. You need to weigh the importance of the number of connections as well as the layover time. Waiting to buy on a certain day of the week and at a certain number of days before your trip can put at risk losing the best connection and layover times. Was it worth the difference in airfare if you now have to stop at 2 different airports before reaching your final destination? Each connection carries its own risks such as the chance for bags to get lost or issues with weather or airplane equipment. The money you might save may seem insignificant if you spend the first two days of your vacation in the same clothes you started in.
3) Time of year. if you are flying to a destination that is popular during a certain time of year (i.e flying to Europe in June or July), the prices will not only change rapidly, but again, flights can literally sell out. The direct flight you wanted from Chicago to Rome not only could be sold out, but the longer connecting flight may also now cost more because you waited.
Let me summarize by telling you how we consult our clients when it comes to purchasing their airfare. If we know that the client's dates are set and we know that destination is a popular one for that time of year, we always encourage them to buy as soon as possible with only a few exceptions. We advise them to consider the single vs multiple connection. We help them see that taking the last flight out may appear cheaper but it may not be worth it if that flight is canceled and there are no longer anymore options out that night. We make sure sure our clients see that the cheaper flight may have a layover until the next morning which means there will be an overnight hotel stay which also now adds to the cost. We make sure our clients know that if it is important that they are seated together, then we need to grab the flights and seats when we can to make sure that happens.
So do you see that waiting to buy airfare on a certain day or picking days of the week that you think will be cheaper may not be the best choice? Its not a simple answer of "always buy on Tuesday because its cheaper." Let professionals help you understand the pros and cons of waiting or not waiting.