As View from the Wing’s Gary Leff says, “Hipmunk adds killer app functionality, has potential to become booking service of choice.” Hipmunk has added functionality that will make building mileage runs much easier–and when you find what you want, you can use the site to book the trip. If you want to do a mileage run on United-marketed flights, you would simply type two colons after your departure city and then specify what you are looking for. For example, to fly on United between San Francisco and Toronto and have two connections, you’d type in SFO::UA UA UA into the “from” field and YYZ into the “to” field. What we found was a stop in Denver and Cleveland on your way to Toronto from San Francisco.

You can also type in particular airports that you would like a connection in. For example, you would type NYC::TYO,HKG in the “from” field, and CGK::TYO,HKG in the “to” field if you want to force a connection in Hong Kong or Tokyo on a roundtrip flight between New York and Jakarta. You can also specify the flight numbers you want. A nifty feature is that once you input a double colon, the site will display various options of what you can request.

And when you’ve found the flight you want, it’s just one more click to buy it on another site. The functionality is in beta, so expect some glitches, but Hipmunk is actively reaching out to frequent flyers with this new functionality so they are asking for feedback if you run into any issues.