The flag carrier for Germany, Lufthansa has announced on Twitter that the airline is working on a Windows Phone app. In response to a question put forward by a follower, it's stated that the development team is working on brining a mobile solution to the store, but no date has been revealed as-of-yet.
@aharpaz Our developers are working on it! So far no release date though, sorry! /Nes— Lufthansa (@lufthansa) March 22, 2013
Unfortunately, as noted in above tweet, we have no idea when the airline expects to release the Windows Phone app. Here's hoping it can't be too long for customers to start enjoying mobile check in, etc.
Source: Twitter (@lufthansa); thanks, Amir, for the heads up!