While fiddling around and trying to check out air fares for a trip for about a month, it appears that when u go over 30 days stay the fare goes up dramatically. Is this always the case? This was on UA.

This is just my take from what I've seen in the past.

The supply / demand algorhythms haven't kicked in. If demand is lower, prices will go down, and vice versa.

I don't think anyone truly understands how airlines use their algorhythms for calculating.

That's a calculated guess. Set a bottom price you'll pay and when the algorhythms hit that price, buy it.

Depends on the route. Some of the cheapest fare class do have restriction in lengths of stay - the logic is that trips longer than a month generally won't be just for leisure. So, no reason for airline to offer the low fare when one HAS TO make this non-leisure trip.

I thought that I agreed with rkkwan, but then I took a look at a few city pairs and found surprising (to me) results.

For domestic fares, I didn't find <i>any</i> that had a maximum stay, other than the 1-year limit on ticket validity. The overwhelming majority of fares (even the very cheapest) didn't even have a minimum stay or a Sat or Sun night requirement.

On the other hand, almost all international economy fares from the U.S. had maximum stays, but all of those maximums were either 3 or 6 months -- I found none of 30 days.

My guess is that OP chose dates for return flights either that had higher day-of-week fares or that had no low-fare seats available.

Thanks! what a PIA.
rkkwan - I think u may have hit the reason. Annoying as it is to a vacation traveler.
DonTopaz - no, that is not what I did. I'm looking at fares from IAD to CDG and if you go over 30 days flying both ways on the cheapest days, then the fare goes up by close to $300. The difference of flying the "off days" versus weekends is only $30 each way.

Almost invariably - when there are fare sales the conditions include the typical Sat night stay, and return flight w/i 30 days.

Rasta's comment fits what I've seen: supply and demand. My in-laws visit from France each winter, and normally they can stay for 2 to 3 months and not have dramatically increased airfare. Last winter was the first time they encountered a doubling of the airfare. I've also shopped for international flights for stays of over 30 days, and have found that prices tend *not* to rise, but sometimes do. janisj is also correct: the sale prices usually have a cap on the return flight.

I will take back my earlier comment. Although the regular fares don't seem to have a max stay, most promotional fares do indeed have a 30-day limit, and those are the only fares that people are typically interested in.

This is unreal to me. It's not 30 days -- its one month. So if you leave in January your return must be by February 28. This is according to the UA rep.

Yestravel, last year when I was planning my trip to Italy, I ran into this. And there did not seem to be any way around it. My friends that were going to come and visit, and return home on the very same plane were going to be paying considerably less than I was.

hi Kodi! I was just struck by the insanity of it Makes no sense to me.

Could it be that the day you are traveling happens to be a high-demand time for one of the locations? i.e., I know that airfare back from Florida to the NE US is very high around the end of April through mid-May due to the snowbirds returning to their winter roosts...

Nope -- it doesn't matter which day I use. And January/February is all low season. If you leave in FEb & return within 30 days into march, fare stays low.

I can sure confirm this. It makes no sense but that's the way it is. It does not matter when it is. Crazy.