Book Thanksgiving flights early this year

• With seven weeks to go until Thanksgiving, airfares for the holiday are up 2.9 percent nationally
• As airlines shrink capacity, travelers may find limited space and higher fares on some routes
• Booking early means a greater chance that families can find seats together

Thanksgiving airline seats and fares are disappearing faster than Aunt Vera's green-bean casserole.

So unless you want the leftovers, book now.

"Of course, there will be last-minute sales, but you'll only get the middle seats on the 6 a.m. connecting flight rather than a nice seat on an 11 a.m. nonstop," said George Hobica, founder of AirfareWatchdog.com, which tracks fare trends. "If you only care about price, then sometimes it pays to wait to buy."

With seven weeks to go until Thanksgiving Day Nov. 22, airfares for the holiday are up 2.9 percent nationally, said Priceline analyst Brian Ek.

The cheapest days to fly for Thanksgiving will be Nov. 13-16, Nov. 22-23 and Nov. 28-29. The most pricey will be Nov. 21 and Nov. 24-25, according to Travelzoo.

As airlines keep shrinking capacity, holiday travelers may find sharply limited space and higher fares on less popular routes, said Dean Headley, associate professor of marketing at Wichita State University, an expert on airline performance.

"It's hard to say what an individual traveler might bump into, but if you are going from a large market to a large market you should find plenty of availability," he said. "The thing that folks from the smaller markets have to know is, in order to get the prices of the past, you have to go from point A to points B and B1 and C. If you make two stops, you can still get that price you may have seen two or three years ago."

In addition, booking early means a greater chance that families can find seats together. And being flexible on flight days also can mean lower prices.

One trend Ek notices is that Priceline's "Name Your Own Price" blind bidding feature is selling Thanksgiving airfares at 20 percent off, a better discount than last year. That indicates that airlines are moving some seats through alternate channels to people who are most flexible on routes and airlines, he said. Passengers name a price and see whether an airline accepts it.

Travelers should pay close attention to baggage fees, which can add hundreds of dollars to the cost of flying.

Checked bags are still free on Southwest Airlines, and if you are a Delta SkyMiles American Express card holder, the first checked bag for each person in your party is free on Delta.

However, two airlines, Spirit and Allegiant, now charge for both checked and carry-on bags.

The nation's airlines performed well last Thanksgiving, with an 85.7 percent on-time record for peak travel days except for the Tuesday before Thanksgiving, which was 78 percent on time, according to federal transportation data. Thanksgiving Day itself was a very quiet day to fly, with 26 percent fewer flights than on a normal Thursday.

This year? With airline consolidation, labor problems at American Airlines and unpredictable November weather, it's anybody's guess."

As an industry, things went relatively well last holiday season," Headley said. "That doesn't mean if something goes wacky with the weather this year, you aren't going to get a disaster on your hands."