I sailed from Venice last year and booked my flights with Jet2 flying out of Leeds. Our flights cost about £145 return. We opted for the private water taxi from the Airport which cost 95 euro which is expensive. We flew out the day before and stayed on a hotel on the Grand Canal.
If you are reasonably mobile a lot of people use the Vaparetto (Spelling?) which is just around 6 euro I think.
I am cruising from Rome 9th October and flying again with Jet 2 . The flights this time cost £112 and we again are flying a day early. The Port is 90Km from the Airport and as the flight is not in until 12.30 it could be a bit neat.
If I had taken the Cruise Company flights it was £380 and we needed to go via either Amsterdam or London.
Do your own flights and if the time is tight my advice would be fly a day early to be sure.
Sue