You cannot use your own frequent flyer (mileage) number for a flight taken by someone else, even a family member. Airline loyalty programs in 2026 strictly require that the name on the ticket matches the name on the frequent flyer account for miles to be credited. If you enter your number into a spouse's or child's reservation, the system will reject the request, and no miles will be earned for that trip. Each traveler must have their own individual account to accumulate miles. However, many airlines offer "Household Accounts" or "Family Pooling" (such as British Airways, Qatar Airways, or Air India), which allow multiple members to link their accounts and share a collective pool of points for redemptions. If your goal is to "use" your miles for someone else, you can do that by booking a reward ticket in their name using your points. In this scenario, you are the "donor" of the miles, but the passenger is the "beneficiary." This is a standard feature of almost all major programs, allowing you to use your hard-earned rewards to fly friends or family members to their destinations.