If we are on the same airline (swisss Air) experiencing a layover in Zurich, must we pass through customs? If so how much time should we allow? Flying from Washington DC to Zurich layover and on to Slovenia. Preferred flight shows only a 50 minute layover. Is this enough? What if we select one that changes to a regional jet but is two different airlines?
I would do it if on one ticket. In my experience, Zurich is extremely efficient.
You go thru passport control. We did San Francisco to Zurich to Venice on a Swiss ticket last September with 50 minutes and it was enough time. Just follow the signs and Don’t dawdle.
You need to book a single ticket, not two separate tickets. On a single ticket if your inbound flight arrives late and you miss the connection, the airline is responsible for getting you to your final destination on a later flight. You will pass through immigration (passport control) in Zurich (both Switzerland and Croatia are part of the Schengen area and Switzerland would be your point of entry) but customs will be when you arrive in Croatia.
I got through Zurich on a connection of less than an hour. It was tight (no time to stop in restroom or buy a bottle of water). My connection was all on one ticket bought through United, but there were two airlines involved (Lufthansa and United)