Absolutely no difference.  Only a handful of near-modern planes (a-10) have any real armor protecting the plane itself.  Pilots often sit in metal tubs, but the overall plane is unprotected from anything physical beyond bird strikes.  Any protection is incidental to the structural requirements.<p>There might be something to say for a metal with a higher melting&#x2F;yield temp that could survive longer in a fire but I don&#x27;t think that enters into the design equation.