Zurich (3.5 h by train, 2.5 h by car)
Bern (2.5 h by Zug, 1.5 h by car)
Basel (3.25 h by train, 2.5 h by car)
Basel and Bern have the advantage, that those are small airports
and there are direct connections to Interlaken OST from Basel City
and Bern City.
Geneva : (4 h by train, 3.25 h by car)