Do I understand correctly that a 24, 48 or 72 hour vaporetto pass in Venice does NOT include a round trip transfer from the Marco Polo airport to Venice?
that is correct
It used to (like when I went in 2010), but it does not now. However, last time I checked, you could add the ACTV airport bus on to the vaporetto pass for a discounted price compared with a normal ticket. If you want to take the ATVO airport bus, that's a separate ticket (and always was).
Once you get to Piazzale Roma, by whichever bus you choose (or taxi if you want), the vaporetto pass then kicks in, to take you to your hotel.
Thanks for your helpful replies! I think we will transfer by veporetto because last spring while we were leaving Venice via bus, the traffic on over the seas road into Venice was at a stand still for miles and miles. Driver told us when that happens you could be stuck on the causeway for hours. We are only there for a day and a half so I’m trying to plan in a way where getting to and fro will use up the least amount of our time.
If you want to travel from the airport to Venice on the water you take the Alilaguna, not a vaporetto.
It is a separate company from the vaporetto system and not covered with a vaporetto pass.