The rule is this: “Air passengers – reads the Dpcm – must necessarily wear a surgical mask, which will be replaced every four hours if an exception to the interpersonal distance of one meter is allowed".  The point is the interpretation: is the surgical mask only the one you buy at the pharmacy? Or are common cloth masks also considered “surgical"? There does not seem to be a clear and unambiguous answer. The civil aviation authority, ENAC, responded only informally – there are no official notes on the site – interpreting the rule in an extensive way, i.e. considering the fabric masks equivalent to the surgical ones (and at this point it is necessary to have two in case of flights longer than four hours). But Alitalia, for example, has interpreted the use of a medical, surgical or Ffp2 or Ffp3 mask as mandatory. So excluding cloth masks.