If you’ve put off purchasing holiday flights, you’re not out of luck. You may still be able to snag a decent fare, but you’ll have to be flexible and choose your dates carefully. Some dates are sky-high, while others are reasonable.

While you typically need to have an advance purchase, the airlines do waive the advance purchase as the holidays near.

Thanksgiving is fast approaching, and we found that the best days to fly are departing today and returning Nov. 23. We’ve also seen decent fares if you depart Thanksgiving Day and return Nov. 27 or later.

The worst days to fly are Wednesday and Sunday. Those are the busiest days, and the fares reflect that. You can save hundreds of dollars by flying on other days.

When it comes to Christmas flights, the best days to depart are Dec. 24 and 25 and to return Dec. 31 or Jan. 1. On the other hand, fares for flights departing Dec. 26 and returning Jan. 2 are very high, and fares for seven-night trips departing Dec. 21, 22 or 23 are also high.

If holiday fares to your desired destination are high, look at alternate airports. If you are flying to Orlando, Fla., look at Tampa, or if you are flying to San Diego, look at Los Angeles. Fares on some dates can be $100 to $150 cheaper by using an alternate city.

If you are planning on a sunny destination like Hawaii, Mexico or the Caribbean during the holidays, expect to pay big. You can save a considerable amount by going between the holidays, or after they are over altogether.

We found the best prices for travel starting Jan. 15. Over the Christmas holidays, fares from Dallas to Maui for seven nights are $1,379 round trip, but fares for January and February average $595 round trip.

Flights from Dallas to Cancun departing Dec. 26 and returning Jan. 2 are $955, but we’ve seen fares for $362 in January. Grand Cayman is $902 for travel Dec. 22-29, but $428 between the holidays or in January. We found flights to San Juan, Puerto Rico, for $960 for Dec. 22-29, $932 for Dec. 26 to Jan. 2 and $310 for travel starting Jan. 15. If you go to San Juan in January, it’s like getting three tickets for the price of one compared with the fares during peak holiday travel.

The fares listed were valid at press time but are subject to change.