United has rolled out a new way to boost mileage balances, although at a cost of about three cents per mile. Basically you can double or triple the miles you earn from a flight you take by registering and giving UA some serious $$$, especially for longhaul flights.
More power to UA if this actually works for them, but it’s far from a great deal, at least in most circumstances. I can see this making sense if you’re 300 miles short of an award and that $9 put you over the edge, but otherwise not so much….
I earn miles at about half of that rate through mileage runs, and that doesn’t account for all of the upgrade instruments and benefits from status that I earn.