We have an early flight out of Marco Polo Airport and we are staying in Venice near the Campo San Stefano. Can anyone tell me if it's going to be possible for us to get to the airport leaving around 5am.
Yes, it is. Check with your hotel and they can give you the schedule for when the vaparetto (sp?) start to run. 4 years ago they were running at 5 AM. You will need to catch the vaparetto to the Roma station, cross the street and then take the bus to the Airport. Again, the hotel can tell you which number bus to catch. Another, more expensive option, is to have the hotel arrange a water taxi that will take you directly to the airport.
Your other option is to take the Alilaguna boat to the airport. It stops at several places, so it's not your quickest trip - but you only have to take one form of transportation.
You have several options. The two above or, what I did because I was stressing I was going to miss my plane, was to get to Plaza Roma and then got a cab. Dropped me right at the door and it was quick and convenient.