By train
Switzerland can easily be reached from all all European countries by
train. Therefore, it's for sure the most recommended way to get there. For transporting bikes it's best to use special transport bags. It's cheaper (free within Switzerland) with it and you get rid of a lot of discussions this way too.
By plane
Most European Airlines are flying into the two big airports
Zurich and
Geneva. Additionally there are smaller airports in
Bern/Belp,
Lugano/Agno and
Friedrichshafen (DE).
By car
Switzerland is well connected to the European highways. However, you have to pay an annual fee to use them. Parking space in the cities are mostly rare and expensive.