I flew with my dog in cabin on four Alitalia flights and each time the crew and check-in staff were very welcoming. The seats don't give you a lot of space on planes going back and forth between Venice and Rome so even though you have tons of room under the seat (no videobox) you have to slide your carrier from the aisle. An aisle seat makes that easier but a window seat gives you more space (I put the carrier on my lap for the window seat since nobody was sitting by me). The do weigh your dog, though! Be prepared. Their policy is up to 10 kg with bag while Air France, Lufthansa, KLM only allow up to 8 kg. I really loved traveling in Italy with my dog (train too - everyone seems super dog friendly).