Among savvy travelers, it used to be a cornerstone of frequent flier program strategy that fall was a great time to redeem airline miles for free flights. Fewer paying passengers meant more available award seats.

There was also a comfort benefit to off-season flying. Flights with fewer passengers give travelers more elbow room, and more space means less stress.

But with the falloff in travel demand during the recent recession, airlines have cut flights significantly. In many cases, they've reduced flights even more than travelers have cut back on flying. Which means that the remaining flights are flying fuller than ever.

Here's how Delta summarized its October results:

• "System traffic in October 2009, including both Delta and Northwest operations, decreased 6.5 percent compared to October 2008 on an 8.3 percent decrease in capacity.

• Load factor increased 1.6 points to 84.2 percent." (Load factor reflects the percentage of seats occupied. And the net result of the month's changes in supply and demand was an increase in load factor.)

The same was true for Southwest:

• For October, the airline flew 2.5 percent more total passengers, and 1.9 percent more revenue passenger miles (number of passengers multiplied by miles flown), than they did a year ago. But the airline also reduced capacity by 9.4 percent.

Simply put, when all the data are sliced and diced, the net result of the traffic increases and capacity decreases was again a higher load factor. The average Southwest B737 was 79.2 percent full during October, compared with 70.4 percent for the same period last year.

Similar forces are in play elsewhere. American Airlines' October load factor was 83.1 percent, up 4.1 points over last year. United's was also 83.1 percent (80.8 percent in 2008).

US Airways flew 82.6 percent full, the airline's best-ever October.

These are high load factors for any month. But they're especially high for a month that historically has been among the year's weakest.

If October's high load factors prove to be more than an anomaly, we could be witnessing the beginning of an era in which flights run full year-round.

That would be welcome news for the airlines, which would be delighted to smooth out the peaks and valleys of travel demand, especially if they can maintain the high load factors. But the all-full-all-the-time scenario is a recipe for discomfort and frustration for travelers.

With fewer empty seats to buffer fliers crammed into narrow coach seats, claustrophobia levels have nowhere to go but up. And not just during the summer crush, when business travelers have always known to minimize their flying to avoid the glut of families bound for Disneyland and Sea World.

For frequent fliers looking to cash in miles for free flights, fewer unsold seats means lower odds of finding award seats available for booking.

While it's too soon to say that fall no longer represents a window of opportunity for award travelers, the evidence suggests that the old rule at least needs to be re-examined.

If discomfort and frequent flier aggravation weren't enough, the reduction of flights to meet flagging demand will eventually give the airlines what they've been seeking: pricing power, the ability to raise ticket prices.

So fliers should prepare themselves for a new chapter in the unfolding travel drama, characterized by paying more for their tickets, enjoying their flights less, and receiving fewer rewards for loyalty.

Not exactly the stuff of advertising headlines.

There is a bright spot among the gloom. With fewer travelers jamming the country's airports, you'll be able to find an empty seat in the departure area. Once onboard, though, that uncongested airport is likely to seem like a distant dream.