Using $ORACLE_HOME/rdbms/admin/awrsqrpt.sql one can generate execution plan from AWR by passing start snap id, end snap id and SQL ID.
It will ask for most of the same inputs like awrrpt.sql, type of report (html/text), start snap id, end snap id, SQL id and report name and create a output in the file specified.
Example:
SQL> @?/rdbms/admin/awrsqrpt.sql