Traveling from Venice to Naples and returning to Venice
We would like to fly; but am confused about the baggage,how many bags you can take aboard,what the weight is,and size. How do I calculate this in the price they offer,so I don't get ripped off at the airport paying an outrageous price? I have read that's what easyjet does.
Or should we take the train for this trip with the eurpass Italy?
Each airline has their own rules.
Take the train but don't buy a pass. For just a roundtrip excursion from Venice to Naples, point to point tickets will be cheaper.
Plus, you get to see the Italian countryside from a train. The only thing you might see from a plane is clouds.
For easyJet, you are restricted to one carry-on of specific dimensions (see their website) but there isn't a particular weight limit. If you know you will have to check any bags, you can pay when booking tickets, 11EUR per bag. If you do not pre-pay to check bags but end up having to do so when you get to the airport, the price will double.
You can use this policy as a rule of thumb for European budget airlines, but do be sure to check with your specific airline's website about specific requirements.