The song that Dean is humming to calm himself down on the plane is called "Some Kind of Monster" by Metallica.
The 15 Most Heartbreaking Supernatural Episodes
"Swan Song" (05.22) ...
"Death's Door" (07.10) ...
"Sacrifice" (08.23) ...
"Do You Believe in Miracles?" (09.23) ...
"Dark Dynasty" (10.21) ...
"Who Are We?" (12.22) ...
"All Along the Watchtower" (12.23) ...
"Despair" (15.18)
