Does this exist - future low airfare alert?

[Cloq]

With airfare prices increasing yearly (or monthly depending on fuel speculation etc.) I was wonder if if a future date low airfare alert email or app exists out there.

Basically looking for something that will check a future travel date and time, on a daily/weekly/monthly basis as prices seem to fluctuate rapidly. 

My local airport use to offer something similar but a few years back they quit doing that. 

[mouser]

I wouldn't mind knowing about such a tool as well -- especially if it was smart enough to check a range of dates..

[40hz]

IIUC, the airlines themselves operate on a totally flexible fare system. So unless they're willing to commit to a given fare on a future date, how would you do that? I've gone onto a airfare sites, got a price, thought about it for a bit, and found out it was gone when I finally went to commit.

A travel agent (who may be wrong - I don't know) told me fare quotes were usually only good for about 10-15 minutes from the moment of request - and were constantly updating and fluctuating in the background because the airlines were juggling them in real time based on actual bookings.

Does anybody know if that's correct?

[tomos]

Does anybody know if that's correct?

the norm here (EU) in my experience is that each flight has X number of cheap seats; Y number of middling priced flights; etc, etc. Usually they will tell you when seats at the current price are nearly sold out.

Approaching the date of the flight I've noticed (imagined?) that the price gets reduced 14 to 7-ish days before the flight, and increased for the week/five-days prior to flight. (I reckon they know that if you're booking in the last week it's because you *need* to fly.)

No idea how this correlates to the US version of events.