I was just reading a book (To Win the Winter Sky, can't remeber the authors name) which is about the air war over the Ardennes offensive. It mentioned the US Ninth Air Force fighter-bombers using napalm (P-51s and P-47s). Sunno how accurate it is in this respect but otherwise it seems to be pretty good.
Let me see if I can find a reference.
EDIT:
see
http://paul.rutgers.edu/~mcgrew/wwii/usaf/html/Jul.44.htmlJuly 1944
"PACIFIC OCEAN AREA (POA, Seventh Air Force): P-47s from Saipan Island, using
napalm-bombs for the first time, hit Tinian and Pagan Islands. Makin Island-
based B-25s pound Ponape Island."
also
see
http://www.telusplanet.net/public/bailart/A_Letter_from_Robert_Bailey/Robert_Bailey_s__Touched_by_Li/_Touched_by_Lightening__-_The_/_touched_by_lightening__-_the_.html"When Coenen arrived in England in January, 1944, no P-47s were available for the group, so they began flying P-38 Lockheed Lightnings from Andover Field, Hants, on Salisbury Plain. Captain Coenen eventually flew 73 missions with 122 sorties. The months leading up to D-Day saw him flying in a variety of roles: bomber escort, dive bombing, strafing, armed reconnaissance and, after the Invasion, ground support for army units. On D-Day he flew three missions over the beachheads, providing cover.
The first Ninth Air Force unit to use napalm in combat was the 370th Fighter Group, during ground support missions in July.
"