General Fare Pricing on Airlines and Why fares are never the same when you call back.
The basic principle for cheap fares is to get in early or get in on a sale, don’t call to make an inquiry and then call back because fares are not guaranteed until ticketed and you could lose your fare. With non-refundable tickets there are so many different prices that it can be confusing, but one of the most common reasons for the difference in fare is advance purchase of 3/7/14/21 days. The closer to the travel date; the more expensive the ticket, and usually there are certain additional requirements such as travel on a Tuesday or Thursday with a Saturday overnight. That means you have to leave on Tue/Thus and the earliest you can return is on Sunday.
Restrictive fares have many rules and these rules are sometimes the reason that you can take a 3pm flight at a lower fare than taking a 9am flight. Peak travel times are generally more expensive and business travelers that do not have a weekend stay can see higher fares.
I’m on the same flight as my friend – why did he get a cheaper fare?
Another reason that fares can differ is due to inventory. Some god-like computer can figure out how many seats can be sold for X and how many at Y, Z, etc. and still make a profit. The combination allows for differences in fares – the airline likes to know how many people will be on the flight, so by purchasing earlier they can count on your occupancy of one seat.
The later your flight the more money you’re going to have to pull in that equation to get to that profit margin. For example the airline decides to sell 22 seats in S inventory for $209.00 base fare, 18 seats in T inventory for $187.00 base fare, 11 seats in K inventory for $144.00 base fare. All of these seats will be attached to a Fare Basis that contains the rules and regulations.
In addition there will be 34 seats sold in H inventory for $280.00 and 46 seats sold in V inventory for $319.00. You can see that there are far fewer seats available at the lower rates so that inventory will sell out first.
If someone calls and selects a flight with the last seat in K class on that flight then all bookings later will not be able to get that same fare. If you are booking to match a friend and they purchased the last seat at that fare then the only other option is to go to the next inventory to get you on the same flight. Note that inventory does not have anything to do with seating; that’s a whole other set of circumstances.