The most convenient airport for Groningen is Schiphol Airport in Amsterdam. It has a direct connection to Groningen train station. For connections, see ns.nl. From the station there is a frequent bus service (see below) to the conference hotel.
Other airports that can be used, with train trips of 2-3 hours: Eindhoven, Bremen, Düsseldorf.
Bussstop Groningerweg 19 - Qbuzz line 9
Use exit nr. 38 on the A28 highway