I will have a 12 layover from approx 10AM to 10PM .... what is the best mode of travel to the city and return to the airport and what is suggested to see during this time?
To answer your question, there is a train station in the airport. In addition to some regular trains, there are about four S-Bahn per hour to the Zurich Hbf. They take 11-14 min. The fare is 3,20 CHF The first thing I would see is the Swiss National Museum (I didn't get to when I was there; it's closed on Mondays). www.musee-suisse.ch/e/index.php
Another option is to take a scenic train journey. With a 12 hour layover it would also be possible to take a train to Luzern (1 hour), transfer to the scenic Golden Pass train to Interlaken (2.5 hours). Transfer to the train to Lauterbrunnen, admire the valley and the mountain peaks, and hop back on the train to Interlaken (1 hour rt). Then take the IC train back to Zurich Airport with a quick change in Bern, and be back in time for the flight (2.5 hours). The best part is that all of these connections are coordinated so there would be minimal waiting around for the next train.
this is a duplicate posting, both in the same board, several answers on the other thread