Venice Marco Polo airport question

An hour and a half to two hours ahead will do the trick.

It's a flight within the EU/Schengen area therefore it works like a domestic flight in the US. Venice is not a big airport so it won't take long to check in and go thru security (and the shoes stay on your feet at all times). 1.5 hours prior to departure is plenty.

and, a couple of nice gift shops to spend your time.........

I don't think the airline matters, an hour and a half to two hours is a good window. Allow plenty of travel time from the island to the airport.

The check-in desks at Marco Polo airport do not open until exactly two hours before your departure time. It takes almost exactly one hour for me to get to the airport, using the vaporetto from the San Stae vaporetto stop, to Piazzale Roma, then to take the Aeroporto bus to the airport. Thus, I usually leave my hotel 3 hours before flight time, and still have plenty of time at the airport before an international flight. Be aware: the passport control at the airport can be quick (5" wait) or long (30-45" wait), so earlier is better, I think.

You don't say how many people you are traveling with or how you intend to get TO the airport in Venice. My family of 4 traveled from the canal next to our apartment in Dursoduro to the airport in a private water taxi. I am usually all about public transportation and thought the taxi was a splurge. It cost 100 Euros approximately 20 Euros more than traveling on the Alilaguna water bus. It was worth every penny of that extra 20 Euros. It was absolutely awesome to glide through the Grande Canal and out into the lagoon and then zip over to the airport - we felt like movie stars. We found the Venice airport to be so easy to navigate. It was a terrific way to end out trip! An hour and a half or two hours should be plenty of time. Have fun!