Try looking under his real name and look for his squadron. Flight Journal magazine has a large article this month about military flying celebrities. Dan Rowan was mentioned but I lent my copy out to a friend of mine so I can't check it.
Edit: try this from Joe Baugher:
104949 (8th FS, 49th FG, "Kathleen II") flown by Lt Dan David who changed his name to Dan Rowan (of the Rowan and Martin "Laugh-In") after
the war. Aircraft DBR Oct 24, 1943 in Hopoi area of Papua New Guinea. Ended up in Australian registry as
VH-DEA
Look up info on the 8th FS, and the 49th FG. Look at Google Images for the group and squadron. You might find it.
Squadron also has a book, The 49th FG. If they don't have it in print now, it is available on Ebay. Osprey also has a book.
Here: http://www.pacificwrecks.com/aircraft/p-40/david/dan-h-david-dan-rowen.html
http://www.pacificwrecks.com/aircraft/p-40/david.html
WIP: Monogram 1/72 B-26 (Snaptite) as 73rd BS B-26, 40-1408, torpedo bomber attempt on Ryujo
Monogram 1/72 B-26 (Snaptite) as 22nd BG B-26, 7-Mile Drome, New Guinea
Minicraft 1/72 B-24D as LB-30, AL-613, "Tough Boy", 28th Composite Group