On Thursday, the strike affects Lufthansa long haul flights. This means that there are no affects on flights between Helsinki and Germany.
On Friday, the strike affects on short and medium haul flights operated by Lufthansa. It's possible that there will be cancellations and delays concering also flights between Helsinki and Germany.
Passengers are kindly asked to turn to Lufthansa in all matters concerning their flights affected by the strike. During the course of 17th of March 2015 Lufthansa will publish a list of affected flights on its web site.
If you'll be departing from Helsinki you can follow your flight status at airport's web site..