I mentioned a couple months ago that United was still running their promotion with Foursquare where you get 50 miles per airport check-in, limited to one per day.
Well, here we are a couple months later, and they’re still running it! If you haven’t signed up, please do. You can be over a mile away from the airport and the check-in still works. Also, while it’s supposed to only work once per day, I have gotten it give me 100 miles for a day, when I check into both the departing and the arriving airport. This tactic doesn’t always work, but it works enough that I try it every time (and it worked earlier today!).
This promotion is especially useful for those of us that drive by an airport on our daily commute! This has been the easiest miles earning promotion I’ve ever participated in, and if United keeps it alive, it will only be a couple of months before I have a one-way domestic coach ticket (12,500 miles) all for checking in with Foursquare.