For most of us, fares drop beginning Jan. 9, 2018. This can vary by a day or so depending where you are but a recent Southwest Airlines sale advertises deals beginning Jan. 9. Once we hit this date, watch for super-deals on U.S. flights and flights to Europe. What does "super" mean? How about New York to Madrid for $376 round-trip sound or Los Angeles to Copenhagen for $341.
This first deal zone of the year generally lasts through much of March but the biggest bargains are usually good for travel in January and much of February.
The first exception occurs in February for the U.S. holiday of President’s Day weekend. This is an increasingly popular time to fly and it’s reflected in higher ticket prices for flights on Feb. 15, 16 and 17.
Another exception is the standard one that it’s generally cheaper to fly domestically on Tuesdays, Wednesdays and Saturdays while Friday/Sunday itineraries are expensive.