I am not sure impersonating a member of airline personnel is, in itself, any kind of crime.
It's Fraud by false representation.
He made a representation which he know to be untrue or misleading in order to make a gain i.e free flights.
Active misrepresentation for personal gain is fraud.
Wandering around in a uniform, talking the talk and allowing someone else to jump to incorrect assumptions is a case of - more fool them.
I am just talking in principle you understand. I do not know all the facts here. And as someone has already claimed - in Italy the dressing up alone is a crime. (No Doctor & Nurse or Vicar & Tart parties there!)