The sim must to be registered. Here we can't sell the sim without register it, I'm a dealer...
You only need Passport or Identity card and Codice Fiscale to buy an Italian sims.
Sorry but I don't know if in Linate airport there are a "Centro Tim" or "Il Telefonino"
But here (in Italy) it's easy to find a cellular shop, and all electronic shop have sims card...and in Milan there are many...
Ask to activate instantly...
