According to The Airfarewatchdog Blog:
Big changes may be coming to the process of buying airfares. That's because ATPCO, the folks who act as the airfare intermediary between the airlines and you, the consumer, via airfare distribution systems such as Travelocity, Expedia, and your local travel agent, will soon be implementing real time, instantaneous airfare updates, according to a person who is familiar with the matter.
Currently, ATPCO (the Airline Tariff Publishing Company) allows airlines to "file" new fares three times a day (10 AM, 12:30 PM, and 8 PM) weekdays, and once a day (5 PM) weekends. But the company, I was told, has been working on a major software update that will allow airlines to file new fares with ATPCO whenever they want, 24/7, even on weekends. (Airfare factoid: the last fare update at 10 PM 8 PM on Friday has been a popular one for the airlines to sneak in a fare sale, since their competitors can't match it until the 5 PM Saturday update, but looks like that strategem will be one for the history books).
This could have huge implications for both the airlines and you, the consumer.
What it means for you is that fares can fluctuate much more frequently than before, which may make shopping for airfares even more of a challenge.
What it means for airlines is that in order to respond to their competition's airfare increases and decreases, they could conceivably have their pricing analysts work in a 24 hour environment. On the plus side for airlines and the online travel agencies such as Travelocity, they'll be able to eliminate fare mistakes almost instantaneously instead of waiting for the next fare update, which could be hours away. On the minus side, airlines might have to add staff to their pricing and fare analysis departments, and really keep on their toes.
Interestingly, the major airlines own ATPCO, but their primary customers are actually the global distribution systems (GDSs) such as Sabre (as well as anyone else who wishes to buy their voluminous--and very costly--airfare data, for example, ITA Software). It appears that the customers are the primary impetus behind this change, rather than the owners themselves.
Of course, there's many a slip between development and launch when it comes to new software, but if this project is successfully implemented and potential conflicts of interest are resolved, airlines will be able to change their fares more often and more quickly than ever before, and consumers will need to keep on their toes like never before.
AmbergrisCaye.com 
