Short trip...Zurich - Lauterbrunnen - Zurich

There is a station at Zürich airport, called Zürich Flughafen. Once you come through arrivals, just look for signs "Bahn/Railway". So unless you arrive really late, there is no need to waste a night in Zürich, go straight from the airport to Lauterbrunnen.
You can look up train times on the SBB (Swiss Federal Railways) website: https://www.sbb.ch/en
All rail lines in Switzerland have at least on train per hour.. The last train of the day to Lauterbrunnen is:
20:40 depart Zürich Flughafen, 23:23 arrive Lauterbrunnen
So it would have to be a very late flight (land after ~19:00) to force you to spend the night in a hotel at Zürich airport.

Again on your return, unless you have an early morning flight, you can get from Lauterbrunnen direct to Zürich Flughafen station and not waste a night at the airport hotel.

The direct and fastest route is Zürich Flughafen - Bern - Interlaken Ost - Lauterbrunnen. If you want a scenic route (and it is still daylight) the alternative scenic route, which takes ~1 hour longer is: Zürich Flughafen - Luzern - Interlaken Ost - Lauterbrunnen. This goes over the Brünig pass.

Passes is a complicated question, you will need to do the arithmetic yourself. It depends on how many mountain railways and cable cars you will use. The main options are:

• Swiss pass
• Half fare card
• Berner Oberland pass. Details here: http://www.regionalpass-berneroberland.ch/en/

The Berner Oberland Pass gives greater coverage for the mountain railways and cable cars than the Swiss pass, but would require you to buy tickets to and from the airport additionally.

It's a personal choice, but we decided to visit the Schilthorn (lifts above the mountain) rather than Jungfrau (train through the inside of the mountain) And it's half the price.

Are all of the "7 of us" adults? If not, what are the ages? Are you arriving at the airport or the train station and at what time? Answer those questions and we can get you a better answer.

1. Don't waste a night in ZUrich
2. With only 3 short days I would not recommend wasting an entire day going to/from the Jungfraujoch.

The whole area is magnificent so don't waste any time in Zurich.

Thank you everyone so much for taking the time to answer. It's been very helpful!!!
All adults over 40. The reason why I was giving us a day in Zurich, is because we are flying standby/space available, and we may or may not make it on our first flight option....we rented an apartment in Lauterbrunnen for the night of the 24th & 25th already, and cannot change dates :-( With the exception of myself, no one else has been to Switzerland.

If you are going to the Jungfraujoch, you should buy 30-day Half Fare Cards when you land. Cost is 120 CHF per person. Then all your train tickets, including to the Jungfraujoch and back will be half price.

As was suggested, just get out of Zurich right from the airport. Go all the way to Interlaken if you can. Or at least to Luzern. When you leave Lauterbrunnen, go back to Luzern. You can get a direct train to the airport Friday morning in just 1 hour. There is one at 7:10 and will get you to Zurich airport by 8:13.

It seems very risky to me to only have a single full day in the Lauterbrunnen Valley at any time of the year because of the highly changeable mountain micro climates and especially at this time of the year.

Conventional wisdom and guidance is to allow at least two or three full days in the area. The weather is changeable and at this time of the year it can be days of rain and/or fog. This years things are even less predictable than usual.

I never advise folk to buy tickets for the Jungfraubahn without checking the screens in their hotels or at the ticket office. No fun getting to the top and finding it looks just like fog does at home.

If the weather is awful for your short stay there are things you can do at low level, but the mud is setting in now or soon on the higher trails. If you wind up doing a train ride (and via the Brunig Pass would be suggestion at least one way (I'd do both ways myself but I'm a sucker for that route)), some walking and one or two low level trains or cable cars you may find that a half fare card won't pay for itself.

If you definitely are going up top it may well do so.

Gotta do the math, I'm afraid.

Good luck getting your flights..... the mountains are pretty nice.

I also chose the Schilthorn over the Jungfrau, based on Rick's comments in his books and his videos. It seems to be the path less chosen, was very enjoyable, you have a choice of two different ways to get up and down, you can get off in Murren on the way down and walk around.

As noted Zurich has two train stations, sorta. The main one in the city and the one at the airport. Hard to mix up. There are several hotel choices right at the airport, we did the Hyatt which was a short bus ride away.