Paris to Lucern

I would definitely take the train. It is a TGV from Gare de Lyon to Basel in 3 hours, then a 1 hour train to Luzern. It would definitely be less time than flying, which would probably take 6 hours when all the logistics are accounted for..

Do you mean when you are coming from the States ? I don't understand.

Are you staying in Paris a few days before continuing to Lucerne? Or trying to go directly from CDG upon arrival from a transatlantic flight. It makes a difference.

I am pretty sure the OP is spending a few days in Paris beforehand. Nothing in the post indicates otherwise.

No, not spending a few days in Paris. We are flying directly from Paris from AZ. We can either get off the plane and get on a train in Paris, or take a shorter flight to Zurich (with a 2 1/2 hour layover), and then take the train from there. We are thinking it may be better to take the train starting in Paris.

That will be logistically complicated. Either taxi or RER train (with a transfer) to Gare de Lyon. Booking a train will be expensive, since you will need a flexible ticket, since you cannot be sure when your plane will land. Just buy a ticket to Zurich and make your life easy. No real scenery from the train.

Plus, at least 1 hour of that 2 1/2 hour layover will be taken up by deplaning and clearing Schengen immigration (passport control). And your luggage will be automatically forwarded on your flight to Zurich. If you decide on the train, you will have to collect it in Paris and be wrangling it to the Gare de Lyon and all the way to Luzern.