To begin earning frequent flyer miles, you must first enroll in an airline's loyalty program, which is almost always free to join. Once you have a membership number, ensure it is attached to every flight booking you make. In 2026, miles are typically earned based on either the distance flown or the amount spent on the ticket, depending on the airline's specific policy. Beyond flying, one of the most effective ways to accumulate miles is through co-branded credit cards, which offer "welcome bonuses" and allow you to earn miles on everyday purchases like groceries or gas. You can also earn miles through "partner" activities, such as booking hotels, renting cars, or using an airline's online shopping portal. Always remember to check if your airline belongs to a global alliance (like Star Alliance, SkyTeam, or Oneworld), as this allows you to earn miles on one airline while flying on a different partner carrier.