Originally Posted by
Happy
... BA has household account you can combine members' balances.
Most US airlines dont have this feature and as others mentioned above, you can "share" miles with a fee. Check respective airline's program on how much it would cost you.
Within *A, BMI has family accounts. Unfortunately, it's a bit late in the day to start crediting miles to their program.
"Sharing" miles is a funny term for what airlines do here. (I know it's the airline's term, not the quoted poster's.) All they do is charge you a fee to move miles from one person to another. It's not like it costs them anything to do the transfer. They're charging for increased likelihood that the miles will be used.
