As far as the original brand, liquidation occurred some time ago. Pan Am's frequent flyer program was taken over by Delta along with various other Pan Am assets, at that time persons who didn't already have a DL account had one opened in their name. As noted there have been a couple sales of the name Pan Am since.
http://www.flyertalk.com/forum/trave...-dead-yet.html
http://www.flyertalk.com/forum/delta...m-account.html
http://www.flyertalk.com/forum/delta...nt-flyers.html
http://www.flyertalk.com/forum/delta...e-account.html
http://www.flyertalk.com/forum/delta...s-history.html
http://www.nytimes.com/1991/09/29/tr...nt-fliers.html