The Qantas app announced at MIX 11 overnight sounds pretty sweet - as well as letting you remotely check in and receive a digital boarding pass, it uses the phone's location software to estimate travel times.
The app will take advantage of the upcoming background processing functions of the phone, which means it's probably months and months away from launch. But it could be exceptionally useful for frequent travellers - the screenshot shows the app offering alerts as to when you should leave in order to make your flight.
While some of the features are available in the iOS Qantas app, the travel time feature is unique to the WP7 version for now. And there's no Android app to speak of yet, which does seem strange given Microsoft's position as the lagger in the mobile OS race.