Sign up for an airline credit card.
If you know you're going to be traveling a lot in the upcoming year, keep an eye on credit card offers. Usually, you can get a deal that waves your signing fee and gives you 10,000-25,000 points (enough for a free flight). Some airlines are even offering two free round-trip flights when you sign up. And points accumulate quickly, if you travel a lot, leading to more free flights.