Due to the International Dateline, the attack on the Philippines took place on Dec 8 - Philippines time, but on Dec 7 in the U.S. and Hawaii. From Air Force magazine Disaster in the Philippines:
Almost all of the American airplanes at Clark—45 miles north of Manila and the main operational base of the Far East Air Force in the Philippines—were lined up neatly on the ground when the strike came at 12:40 p.m. Japanese A6M Zero fighters followed the bombers, dropping down to strafe the ramp. The fighter base at Iba on the western coast of Luzon, 42 miles from Clark, was struck almost simultaneously.
By end of the first day, the strength of Far East Air Force was reduced by half, and it was eliminated as an effective fighting force. The FEAF response was scattered and ineffective. Of approximately 200 aircraft in the Japanese strike force, all but eight returned to their bases on Formosa.
Air superiority established, the land invasion began. The fighting continued for several months, but the Japanese victory was inevitable, leading to a surrender of US forces on May 6, 1942.
It was not as if US commanders in the Philippines had no warning. Ten hours had elapsed since the devastating Japanese attack on Pearl Harbor, where in addition to the naval losses, the US air forces were caught on the ground. Now, it had happened again.
When Pearl Harbor was struck at 7:55 a.m. on Dec. 7, 1941, in Hawaii, it was 2:25 a.m. on Dec. 8. Reports reached the Philippines soon afterward. In addition to warning messages received, the movement of Japanese aircraft was detected by radar and ground observers and there were several preliminary attacks.
Maj. Gen. Henry H. “Hap” Arnold, chief of the Army Air Forces, called FEAF commander Maj. Gen. Lewis H. Brereton to ask, “How in hell could an experienced airman like you get caught with your planes on the ground? That’s what we sent you out there for, to avoid just what happened. What in the hell is going on there”
The question has never been answered satisfactorily. Pearl Harbor generated 10 official investigations. The senior officers in Hawaii, Adm. Husband E. Kimmel and Gen. Walter C. Short, were relieved of command and forced into retirement. By contrast, there was no official investigation of events in the Philippines, and no one was held accountable.
More at Pacific Eagles:
At 0300 local time on the 8th of December, the famous ‘Air Raid Pearl Harbor’ message was received in the Philippines. The FEAF was instantly put on alert, with pilots ordered to stand by their aircraft. Within 30 minutes, unidentified aircraft were detected by Iba’s SCR-270 radar set and P-40s were sent to intercept, but they failed to find the incoming aircraft (probably reconnaissance patrols) in the darkness. At 0500, official word came from the US that the war was underway. When notification of the Pearl Harbor raid was received, the FEAF’s commander Lt.Gen. Lewis H. Brereton immediately requested permission to send his B-17s to attack Japanese airfields in Formosa. He was unable to talk to MacArthur to gain authorisation, so as a precaution had his B-17s take off to prevent them being caught on the ground. Shortly afterwards a large formation was aircraft was discovered coming in from the north.
This formation was a strike that had been launched in the early hours. Japanese Army bombers arrived over northern Luzon around 0800, as the 8th Sentai attacked Tuguegarao airfield and the 14th Sentai’s Ki-21s bombed Baguio barracks. As with the earlier contacts Iba’s radar set had detected the intruders but Brereton’s P-40s were deployed to protect what were deemed the most important facilities in the Philippines – Manila and Clark Field – not Baguio, and so the bombers were able to complete their attack unmolested. Davao on the southern island of Mindanao was also bombed by aircraft from the small carrier Ryujo, with two of PatWing10’s PBYs destroyed on the water. Thick fog covering Japanese Navy airfields on southern Formosa delayed the launch of the 11th Air Fleet’s own bombing raid by several hours, the planes not departing until 0930 – less one bomber which crashed and exploded during the takeoff.
Eventually, MacArthur contacted Brereton and authorised the strike on Formosa. The B-17s were recalled to Clark to refuel and bomb-up for the mission. Most of the fighter aircraft that had been launched before the 5th Air Group’s raids were also running low on fuel and had to land, and the 3rd Pursuit Squadron which had been sent on a fruitless hunt over the South China Sea was ordered to return. Therefore the vast majority of the FEAF was on the ground when the 11th Air Fleet’s bombers arrived just after 1pm. Flying in perfect V formations the Japanese bombers were completely unopposed.
And more from here:
According to the Japanese plan for the capture of the Philippine Islands, naval air units would assume the initial responsibility for destruction of defending air and naval forces and for cover of the landings. When beachheads had been established and Philippine airfields had been captured, army air units would move in for the purpose of supporting the ground forces. The first air assault was scheduled for early morning on the same day of the attacks in Hawaii.18
Preparations had been well under way by the opening of November. During the first two weeks of the month, land-based naval air units of the 11th Air Fleet were transferred to Formosa, where with approximately 300 planes they entered into intensive training in day and night bombing, long-range reconnaissance, air coverage, and strafing attack. As December came in, the Third Fleet was engaged in assembling its main forces at Formosa for the amphibious invasion of the Philippine; and to the naval air strength deployed at Formosan bases were added 150 to 175 planes of the Fifth Army air force. The main weight of army aviation was deployed in the south for support, initially from Indo-Chinese bases, of the conquest of Malaya.19
For defense of the Philippines, the Far East Air Force had in commission thirty-three B-17's, of which sixteen were at Del Monte and the rest at Clark Field, and approximately ninety pursuit aircraft.20
The 3e Pursuit Squadron at Iba and the 17th at Nichols each had eighteen P-40E's; the 20th at Clark was equipped with the same number of P-40B's. The 21st and 34th Squadrons, respectively based on the Nichols and Del Carmen fields, had arrived in the Philippines only in late November and did not receive their planes until 7 December, when the former was assigned approximately eighteen hastily assembled P-40E's and the latter took up its duties with P-35's, each of which had an average flying time close to 500 hours.l Also available were a miscellaneous assortment of noncombat aircraft and twelve P-26's flown from Batangas by pilots of the Philippine Air Force.21
Had the Japanese been able to keep to their schedule, the attack on the Philippines would have coincided much more closely than it did with that at Pearl Harbor. But inclement weather above Luzon delayed execution of the plan for an early morning attack, and gave the Americans advance notice of several hours.22 In fact, the major attack on Clark Field, where virtually half of our total bombing force was destroyed on the ground, did not develop until after noon, some nine hours following the initial bombing of Oahu.
In the Philippines, which lie on the other side of the international date line, it was Monday, 8 December, when shortly after 0300 (0830 in Hawaii) a commercial radio station picked up a report of the Pearl Harbor attack.23 Though no official confirmation was immediately available, base commanders received prompt notification and all units were placed on combat alert. Within thirty minutes of this first warning, the radar set at Iba plotted a formation of aircraft about seventy-five miles offshore headed toward Corregidor. The 3d Pursuit Squadron immediately sent out planes for interception. As the radar followed the course of the outgoing P-40's, it showed them making contact with the approaching aircraft, after which the latter swung off to the west and their plots disappeared. It was later learned that our pursuits actually had made no interception. Apparently, the P-40's in the darkness had passed underneath the enemy planes.24 There were not other alarms prior to receipt of official confirmation of the outbreak of hostilities with Japan by 0500.
A plan of action which had been considered for this eventuality by the Far East Air Force was an American air attack against Formosa, the natural point of concentration for a Japanese invasion of the Philippines.25 Objective folders, although without calibrated bomb target maps or aerial photographs, had been prepared,26 and Col. Francis M. Brady, chief of staff to General Brereton, promptly took the initial step toward mounting the operation by ordering the B-17's at Clark Field prepared for the mission.27 Brereton himself reported at about 0500 to General MacArthur's headquarters at Fort Santiago, where he requested permission of Brig. Gen. Richard K. Sutherland, chief of staff, to carry out offensive action as soon as possible after daylight.28
That request, unhappily, has become a subject of controversy. Conflicting statements have been made and the historian is left to find his way without the aid of a complete record. Indeed, only a few fragments of the official records of the Far East AiR force survived the initial engagements and movements of the war, with the result that chief reliance must be placed on the recollections of its personnel. It would appear that the files of General Headquarters, Southwest Pacific Area, are also incomplete.29
Since the question turns so largely on evidence drawn from the memory that men carry of the first hectic hours of war, it seems pertinent to observe here that there can be little doubt that to the airmen of General MacArthur's command the logical defensive use of the long-range heavy bomber in the circumstances existing was to strike at the enemy's concentration of air and naval power on Formosa, and to strike before the enemy could attack.30 Not only would this have been in accord with standard AAF doctrine and with the mission in defense of our own shores for which the B-17 originally had been designed, but Formosa lay well within the range of the plane, which incidentally had been built for missions extending beyond the distance for which fighter escort could be provided by current models of pursuit aircraft. It is true that the number of planes available was nowhere near that required for a decisive striking force, but the defensive value of the B-17 lay almost entirely in its offensive power and the alternative to its use in that manner was to save it for possible destruction on the ground. Moreover, the mission presumably would serve useful purposes of reconnaissance, and it would have been accordance with the recent revision of RAINBOW No. 5. [See above, pp. 184-85.] If General Brereton did not propose an early undertaking of offensive action against the enemy on Formosa, as both officially and publicly he has stated he did, it would be surprising indeed.
Following the publication in 1946 of The Brereton Diaries, in whichfor the first time General Brereton publicly stated the facts as he recalled them, General MacArthur announced that he had received no such recommendation and that prior to that publication he knew "nothing of such a recommendation having been made."* This statement lent special weight to the testimony of General Sutherland, who during the preceding year had stated in an interview that the responsibility for holding the bombers on the ground that morning was entirely Brereton's.
It was Sutherland's recollection that the air commander agreed that there would be no point in attempting a bomber mission without advance reconnaissance. The interview did not indicate whether the question of an immediate reconnaissance mission was considered, but General Brereton, in reply to a request for information on that point, has indicated that no authorization for reconnaissance was received until later. "At the first conference," he wrote, "General Sutherland approved my plans for an attack immediately after daylight, instructed me to go ahead with preparations and that in the meantime, he would obtain General MacArthur's authority for the daylight attack."31
The record of an interview by Walter D. Edmons with Lt. Gen. Richard K. Sutherland in Manila on 4 June 1945 (copy supplied the author through the courtesy of Mr. Edmonds) reads on the question of "Why was Formosa not bombed?" as follows:
Gen. Sutherland began by saying that all the B-17s had been ordered to Del Monte some days before. On a check it was found that only half had been sent. GHQ wanted the planes in Del Monte because they would there have been safe from initial Jap attacks--they could not have been reached at all--and they could themselves have staged out of Clark Field to bomb Formosa. This direct order had not been obeyed. And it must be remembered that GHQ gave out general orders and that the AFHq were supposed to execute them. As Sutherland recalls, there was some plan to bomb Formosa, but Brereton said that he had to have Photos first. That there was no sense in going up there to bomb without knowing what they were going after. There were some 25 fields on Formosa. On December 9th and 10th, photo missions were dispatched--Carpenter going on the first and returning with generator trouble; Connally going on the second but being turned back by fighters. Holding the bombers at Clark Field that first day was entirely due to Brereton. (Italics mine, WDE.)
General Sutherland's statement that all B-17's had been ordered to Del Monte (subsequently confirmed in MacArthur's statement of September 1946) and General Brereton's account of the move have been discussed above in Chap. 5, pp. 188-89. On the immediate question of the employment of the planes at Clark Field on 8 December, the question of a prior order for their transfer is a side issue.
[The official US Army history, published in 1952, gives greater weight to Brereton's version that the Sutherland/MacArthur version! Note particularly, the discrepancy in MacArthur's supposedly holding back the bombing attack in favor of a reconnaissance mission, then later the same day authorizing the bombing mission in spite of the lack of reconnaissance. Considering other events, and MacArthur's non-appearance throughout the morning of that critical day, this student believes that a plausible explanation is the MacArthur suffered at least a mild nervous breakdown upon receiving the news of Pearl Harbor--and realizing his inevitable defeat in the Philippines--and that Sutherland's primary task that morning was to get the "boss" to pull himself together and assume effective command. After the efforts that MacArthur had initiated to repudiate the long-standing strategy of 'delay-and-defend until the fleet could arrive to reinforce', in favor of an aggressive forward defense relying largely on the striking power of the B-17s he demanded, it boggles the mind to discover another believable explanation for his failure to even meet face-to-face with his air force chief that morning. Further evidence of his tenuous response to events is the continued commitment to a forward defense of the beaches, until precipitously abandoning those plans in favor of the retreat to Bataan immediately after the Japanese landing at Lingayen Gulf--too late to move the mountains of material needed to feed and support his army. HyperWar] (emphasis added)