Some earlier comments after my last post seem to misunderstand the situation (I certainly did not realise until a few months ago either). However, there is a great overview here on the FT website.
In fact there is loads of detail in the link that has been omitted on earlier comments, including German translation.
FT Alphaville » Blog Archive » BMI ‘Kinder-Surprise’
I quite like the new airline name they give it...B-mi kinder surprise...!
Deutsche Lektionen jedermann?