Pan Am = bankrupt in 1991 (Delta purchased some of the remaining assets). New airline under the Pan Am name came out in 1996, lasting until 1998. A third airline using the name operated from 1998-2004.
Eastern = bankrupt in 1991, new airline under the name is planned for 2014 (we'll see)
Continental = merged with United in 2012 - they kept the United name and the Continental tail scheme
Allegheny = changed its name to USAir in 1979