While MacArthur may have had many personal flaws, on his leadership in the Philippines I find little reason to complain, particularly on the popular admonition that he "mishandled his air force" - ususally with reference to the non-decision to attack Formosa (on which permission was given later during the day) with his B-17's immediately upon the message that Pearl Harbor had been attacked by the Japanese. First of all, the US B-17 bomber force had very little intelligence on Japanese targets and the whereabouts of their units on Formosa. Formosa was off-limits to US air reconnaissance even if the Navy's PBY's had often skirted its Southern tip. However, what information the Navy did obtain wasn't necessarily relayed to the Army (USAFFE).
Secondly, to send these bombers unescorted on such a mission could have yielded as much losses as the OTL did. (MachArthur airs this opinion in his own book). Sent out early in the morning they might have crossed the tracks of the soutbound Japanese bomber force. On their way back they might have dumped into the returning japanese force. The Japanese fighter escort element actually had been advised to look out for any US bomber forces on their way to Luzon. Those fighters who eventually should peel off to attack such a force had even been assigned to this mission (Saburo Sakai).
Thirdly, the US bomber philosophy proved to be very inefficient when used in such small numbers and from the routinely used altitudes, 20.000-25.000 feet. Well, this can of course be seen as too retrospective but "MacArthur's Air Force" had its own professional commanding officers that should know this better than the General. There was Brereton, group commanders and squadron commanders. What Brereton, in the larger picture, should have thought about was to scout, and eventually attack, any Japanese landing forces closing in on the coastline. That could have been of some use.
Just my opinion.