Flights around the holidays can be some of the biggest travel expenses of the year. At a certain point — maybe while you're stuck in your Uber at the peak of holiday airport traffic — you might begin to wonder if there’s an easier and cheaper way to get to your destination.

One unconventional way to save is to celebrate an un-Thanksgiving — but if Grandma insists that Turkey Day can’t be celebrated any other time, you might have to be creative with which days you choose to fly.

NerdWallet analyzed the past three years of checkpoint travel numbers provided by the Transportation Security Administration, which tracks the number of passengers screened daily at U.S. TSA checkpoints. Because flight pricing is incredibly sensitive to demand, the most crowded days generally correlate with the most expensive days to fly and the least crowded days usually mean you can find savings or book a better flight (like a nonstop flight).

Cheapest days to fly around Thanksgiving

The cheapest day to fly around Thanksgiving is generally Turkey Day itself.

If you cannot travel on Thanksgiving Day itself, here are the three least-crowded days to travel ranked from least to most crowded for both pre-holiday and post-holiday departures. Because they're less crowded and likely less expensive, it makes them some of the best days to fly around Thanksgiving.

Pre-holiday:

Saturday before.

Monday before.

Tuesday before.

Post-holiday:

Wednesday after.

Black Friday.

Giving Tuesday.

Cheapest days to fly around Christmas

Because winter breaks are a bit more spread out, you have many more affordable options when it comes to Christmastime travel. Based on Hipmunk’s historical data, departing on Christmas Day or Christmas Eve makes for the most inexpensive flights, with median round-trip prices for domestic flights under $400. Most people choose to depart earlier, with 68% of people booking flights departing between December 21-23.

As far as return dates, it’s about equally as busy to depart on any of the four days after Christmas. On average, the cheapest itineraries (that aren’t super-short trips) are Dec. 24-28 or Dec. 25-29. The most expensive itineraries are those for the entire week surrounding Christmas, like Dec. 21-29, which has a median price of $547 on round-trip flights in the U.S.

When to book

The earlier, the better. If you can book in the first week of September, you could save an average of 19% on Christmas flights, or 12% of flights for Thanksgiving, compared to peak prices. For Thanksgiving flights, you might also find some lower prices from Halloween through mid-November. Check Christmas bookings again the first week of October or early December.

However, be aware that waiting could cost you your seat on a nonstop flight, or force you to fly at inconvenient hours as availability becomes more limited.

The bottom line

Play with dates in Google Flights or use the Southwest Low Fare Calendar. If you have the flexibility to work remotely or take time off around the holidays, it could save you $100 or more to fly on lower-demand days. The same goes if you’re trying to book a flight using your travel rewards. Many U.S. airlines offer different levels of award pricing based on demand, so you might be able to spend fewer points if you fly on the cheaper days.