A breakdown of travel hacks for 2018 has named January 31 the cheapest day of the year for domestic travel in the U.S., and March 19 the cheapest day for flying internationally.

Online booking site Kayak has released its annual Travel Hacker Guide, revealing some of the biggest trends and hacks for travel in 2018.

If you need to travel within the U.S. in the next few weeks, the results of the report suggest booking January 31, when airfares are expected to be at their cheapest.

For flexible flyers shopping for a cheap holiday abroad, March 19 has been deemed the cheapest day for international flights.

Analysts have also named 2018 the year for European travel: Of the top 10 trending destinations -- defined as destinations with the greatest percent increase in year-over-year searches -- seven are situated in Europe.

Likewise, median airfares to many European destinations are expected to be the cheapest they've been in three years. Prices for hotspot cities like Barcelona, Amsterdam, Lisbon, Madrid, Paris and Rome are expected to drop this summer.

For a cheap and cheerful staycation, experts recommend heading to Denver, where the median airfare rarely goes over US$250.

Meanwhile, budget-conscious travelers may also want to look at Kayak's top 10 most wallet-friendly trips of 2018. For the list, the average trip cost was determined by looking at the 100 most searched for flight destinations, with the lowest overall median trip cost (flight + 3-night hotel stay).

1. Guadalajara, Mexico

2. Calgary, Canada

3. Orlando

4. Raleigh

5. Denver

6. Fort Myers

7. Tampa

8. Salt Lake City

9. Minneapolis

10. Baltimore