Still, I find those flights to MUC somewhat odd in that they will cannibalize the BRU flights to a certain degree.
And ... at LGG there´s no "regional competitor" to be driven out of the market ...
LGG´s local PTP market for MUC is way too small to justify these flights.
The only real ratio I can see behind this move is an attack against AF/KL/Skyteam
and - to a lesser degree - BA.
Choosing LGG over MST is logical in this context despite the local PTP demand ex MST is slightly higher than ex LGG.
I am certain that LH does not target Travellers from the Aachen region although LGG is certainly a useful alternative to flying from DUS/CGN/FRA - in particular because of much less traffic on the Autobahn/Autoroute (plus cheaper parking at LGG)