Venice- Transportation to Airport???

There's the wheeled bus from Piazzale Roma, and there's the Alilaguna boat. The wheeled bus is cheaper, but the Alilaguna isn't terribly expensive either.

It depends on where you are staying in the city. If you are staying close to the train station, the bus is very handy. If you are further into the island the boat stop might be more handy.

We are close by, Calle dei Botteri, San Polo, Venice.

Which is the best transportion for us from there to the Airport?

Go to the Rialto Mercato vaporetto stop and take the No 1 boat to Piazzale Rome, then the No 5 bus to the airport. If you get a vaporetto pass, you can add the bus on when you purchase the pass for 6 euro, Otherwise, the bus is 8 euro.
Oh the water taxi? 100 euro.

What's the website for boat no. 1?
Thanks

I think it might be better for me to ask what your specific issue is. The site www.actv.it has all the boat schedules, but may be a bit difficult to navigate. Its English version is even trickier.
The actual boat schedules are here: http://www.actv.it/sites/default/files/ultimorario.pdf

I think the relevant question would be, what time is your flight? During the day, starting at 5:00 a.m., the vaporetti come about every 10-12 minutes, but the night vaporetti have a much less frequent schedule.