If you still need to book flights for the holidays, now is a good time to book domestic flights at decent prices, according to data from an online travel agency.

That's because this time of year falls in the "sweet spot" for booking domestic flights in advance of the holidays. Domestic flights 50 to 100 days in advance cost about $85 less on average, according to Expedia and Airlines Reporting Corp. in an earlier report on air travel trends. The lowest average prices were 57 days before departure, according to the data.

International flights require more advance notice for the cheapest prices, with the lowest prices 150 to 225 days out, the report said.

November 18, 2014 Atlanta - Travelers wait at baggage claim area at Hartsfield-Jackson International Airport on Tuesday, November 18, 2014. HYOSUB SHIN / HSHIN@AJC.COM

Credit: Kelly Yamanouchi

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Credit: Kelly Yamanouchi

To avoid crowds, Expedia said its data from 2014 showed the least crowded days for holiday travel for each holiday are the Sunday before Thanksgiving, the Sunday before Christmas and New Year's Eve.