Aye because he didn't order an immediate strike and basically dithered about what to do, the refuelling fighters were IIRC to escort the bomber strike that never happened so they just circled the airfields until they had to land at which point the go order was given and by the the IJA was delivering explosive presents. The airforce contingient when it heard about Pearl pressed for an attack ASAP, but he refused to give it. If I recall, he didn't have a good working relationship with the airforce chap in command (wasn't one of his sypcophants) either. Regardless though it was his dithering and hesitance that meant they gave up a good chance at hitting the IJA air bases on Taiwan and gave up the initiative.
Basically MacArthur was a superb figurehead, the press loved him and he loved the press, but he bought into his own hype and unlike Patton, who the US press also hyped up, he lacked the ability to back it up.
Again, this is incorrect. The commander of the Far East Air Force, Major General Lewis Brereton, requested authorization to conduct a bombing attack on Japanese-held Formosa (today's Taiwan) the morning of 08 December, just after receiving word of the attack on Pearl Harbor. Circa 0500, MacArthur's Chief of Staff, Brigadier General Richard Sutherland, told Brereton to go ahead and begin preparations, and he'd get authorization from MacArthur. At 0800, Brereton received a call from Chief of the Army Air Forces Henry "Hap" Arnold, who told him not to let his planes be attacked on the ground. Brereton put three pursuit squadrons and every bomber that would fly in the air by 0830. Some time between 1015 and 1100 (accounts differ), Brereton received authorization from MacArthur via telephone. Between 1035 and 1045 at Clark Field (the main airbase), the bombers and some fighters were landed so the planes could be refueled, the crews fed and, after authorization arrived, the bombers armed with 100 and 300 pound bombs for the Formosa attack. At about 1100, the telephone and telegraph lines at Iba Field, a secondary airbase that housed the FEAF's radar, went dead (sabotage is suspected), leaving them with only the relatively unreliable radio to communicate with other bases. At 1127 and 1129, the radar at Iba Field detected two waves of planes, and surmised that their target was Manila. Three of our available fighter squadrons were sent to intercept the enemy planes before they reached Manila, and the fourth squadron, based out of Del Carmen field, were sent orders to guard Clark Field, but never received them. A fifth fighter squadron based at Clark received no orders and only attempted to take off when a 1LT saw incoming bombers and ordered the scramble himself. As such, the simultaneous Japanese attacks, which were actually targeted at Clark and Iba themselves, caught the airbases by complete surprise. the rearming bombers at Clark were destroyed, along with the grounded fighters that were trying to scramble. Iba was actually hit as some fighters that had been on patrol were landing, with 4 of 6 pilots killed in their planes on the runway (radar there at Iba had apparently been trying to warn them off, but the flight leader's radio was malfunctioning). These attacks destroyed half of the Far East Air Force's planes. Several more B-17s were lost in succeeding days in ground collisions and crashes on takeoff, and on the 17th (9 days after the initial assault) they were withdrawn to Australia. The fighters at Del Carmen that hadn't received orders to defend Clark Field were also destroyed on the ground. In the 2 days following the first strike, more than a quarter of the FEAF's remaining P-40s were destroyed trying to intercept Japanese bombers. Weeks before the attack, Brereton had been ordered to move his bombers to Mindanao, beyond the range of Japanese attack, and had only moved half of them.
So which part of that was MacArthur's fault? When his air commander only moved half his bombers out of range of air attack? When he authorized the requested strike on Formosa? When the telephone wires at the base with radar were disabled 30 minutes before the attack? When the radar operators misinterpreted the course and target of the attack, and routed interceptors to the wrong place? When orders that did go out didn't reach their destination? When B-17 pilots had wrecks on the ground, or crashed on takeoff? None of it is.
There's actually even more to it than that, SNAFUs involving Brereton trying to send out reconnaissance missions only to be informed that the recon cameras were at another base, sending a plane to go get them, fighters flying without supplemental oxygen (meaning they couldn't have reached the altitude the Japanese bombers were at anyway) planes having to turn back due to oil leaks, and on and on. But there core narrative is confusing enough, there's no need to type ten pages worth of all the various issues.
