What is the best way to get from Marco Polo airport to San Marcos?

[feester]

I'm off on a romantic weekend away on Friday with my dh but unsure about the best way to get into Venice from the Airport. Any suggestions?
Dh booked flight home for 6 on sunday didn't realise it was 6 in the morning! How do I get back to the airport at 4.30 sunday morning?
Help

Water bus. You can buy tickets at the airport.

Will they be running on the sunday morning? Do you know how much it is likely to cost? Thanks for your help

I can't remember TBH, but if you go to any bookshop and sneak a look in a Venice guidebook, it will give you up to date info.