The best time to book trips for the Thanksgiving and Christmas holidays starts now and won't last for long, according to travel experts. 

Prices fluctuate throughout the three to five months before the holidays, meaning there are good deals around. As we get closer to those holiday dates, though, cheap tickets are harder to come by. 

"Ahead of time, airfare changes a lot in a way that's unpredictable," said Scott Keyes, founder of travel deals site Going.com. "Some days it's up, some days it's down, whereas in the close booking period, last-minute tickets move in one direction, and that's up."

Keyes said travelers have a couple more weeks to lock in good deals during what he calls the "Goldilocks window" for making reservations.

"I wouldn't put it off later than mid-October," he said. 

Don't wait any longer to book Thanksgiving travel. "Now is the sweet spot," added Hayley Berg, chief economist at flight search site Hopper. "It is also the right time to book for Christmas, which a lot of travelers miss. They'll book Thanksgiving but wait to book Christmas."

Avoid booking last-minute

Indeed, when planning a trip the booking can be as important as the date on which you choose to travel. 

Avoid booking last-minute, which is considered as far out as six weeks before the holidays, Keyes said.

"Prices really spike during that last month before the holiday. They tend to get significantly pricier," he said. 

Berg advises travelers to book Thanksgiving holiday flights by October 14 at the latest. "You'll want to book by then to ensure you're getting the best deal," she said.

Data from flight search site Kayak also shows that the best time to book for good deals is roughly 50 days in advance.

"Now is a great time to book Thanksgiving travel," Kayak's chief economist Jake Bouvrie told CBS MoneyWatch. "The best time to book for Christmas is about 50 days in advance."

When to fly

The site's "Best Time to Travel" tool also shows consumers when ticket prices are lowest for specific holidays. 

"The timing matters — picking those correct dates to travel can be critical," Bouvrie said.

For example, the cheapest day to fly around Thanksgiving is on the Monday before the holiday. For Christmas, the cheapest day to travel is on Christmas Eve.

"Everyone wants to be there on Christmas Day, so if you want to have a couple of days at your destination before Christmas Eve, prices are much higher," Bouvrie said. 

Specifically, to save money and miss crowds, avoid traveling on December 22, he said. "It's one of busiest days of the year; that's where we are seeing the most searches."

Fly on the holiday

To save between 25%-30% on ticket prices, consider flying on the holiday itself, if your schedule allows. 

"For obvious reasons, people prefer to be at the destination on the holiday, not traveling," Keyes of Going.com said. "If you're flexible, that's a technique that can be used to get the cheapest ticket possible."

As far as return dates go, the best day to travel home is the day after Thanksgiving. The worst day? Sunday. 

"The absolute worst day you can fly home from the Thanksgiving holiday is Sunday. You will pay hundreds of dollars more," Berg said. "You could spend up to $400 more than what you'd pay to fly at 6 a.m on Monday morning."