Background As a lower-priority theatre, the Allies had comparatively few modern aircraft to challenge the Japanese. In addition the Allies did not consider Japanese aircraft a significant threat. In 1941 the Allies assumed that Japan would only have a few hundred poor quality outdated aircraft. The respected ''Janes All the World's Aircraft'' for 1941 indicated that the Japanese only had a cluster of dated foreign and indigenous aircraft. Japanese pilots were also underrated, considered unlikely to make particularly good pilots. Prior to the invasion on 8 December there were 75 Allied aircraft stationed in northern Malaya and 83 in Singapore. The only fighter squadron in northern Malaya was No 21 Squadron RAAF that was equipped with 12 Brewster Buffalos. The Japanese had at least 459 aircraft available.
Japanese aircraft and units The Japanese Navy's
22nd Air Flotilla (22nd Kōkū-Sentai) with 110 aircraft and commanded by Vice Admiral Matsunaga Sadaichi operating out of three air bases near
Saigon took part in the initial attacks on Malaya. The 22nd Air Flotilla included the 22nd
(Genzan), Bihoro, and Kanoya Air Groups (or
Kōkūtai). The Genzen Air Group was a key participant in the sinking of the British
capital ships
Prince of Wales and
Repulse off the coast of Malaya on 10 December 1941, losing one aircraft and its crew during the battle. On 22 January 1942, bombers from the Genzan Air Group attacked
Kallang Airport in
Singapore, and subsequently provided air support for Japanese offensives in Malaya including the
landings at Endau. The Japanese 3rd and three of the 5th Air Corps took part in the Malaya Campaign. In total there were 354
Imperial Japanese Army Air Service (IJAAS) first line aircraft involved together with the 110
Imperial Japanese Navy Air Service (IJNAS) aircraft. The Army units were variously equipped with fighters:
Nakajima Ki-27 Nate,
Nakajima Ki-43 Oscar,
Mitsubishi Ki-51 Sonia; bombers:
Kawasaki Ki-48 Lily,
Mitsubishi Ki-21 Sally,
Mitsubishi Ki-30 Ann; and reconnaissance:
Mitsubishi Ki-15 Babs,
Mitsubishi Ki-46 Dinah. Its engine had fuel starvation problems and poor supercharger performance at higher altitudes. Maneuverability was poor and the engine tended to overheat in the tropical climate, spraying oil over the windscreen. In service, some effort was made to improve performance by removing the armour plate, armoured windshields, radios, gun camera, and all other unnecessary equipment, and by replacing the .50 in (12.7 mm) machine guns with .303 in (7.7 mm) machine guns. The fuselage tanks were filled with a minimum of fuel and run on high-octane aviation petrol where available. Many of the pilots lacked adequate training and experience. For example, 20 of the original 169 Buffalos were lost in training accidents during 1941. Those fighter pilots with experience had been trained in methods that were very effective against German and Italian fighters but suicide against the acrobatic Japanese Nakajima Ki-43 "Oscar" and
Mitsubishi A6M "Zero" fighters. A counter tactic of avoiding dog fights with a 'slash and run' attack was developed by Lieutenant-General
Claire Lee Chennault of the
Flying Tigers but was too late for the Allied pilots serving in this campaign. Two days before the attack on Malaya, Hudsons of No 1 Squadron RAAF spotted the Japanese invasion fleet but, given uncertainty about the ships' destination and instructions to avoid offensive operations until attacks were made against friendly territory,
Sir Robert Brooke-Popham, Commander-in-Chief of
British Far East Command, did not allow the convoy to be bombed.
Air campaign responding to a scramble order On the first day, the focus of the Japanese air assault was on the Allied air bases. Mitsubishi Ki-21
Sallys from the 7th Hikodan bombed the airfields at
Alor Star, Sungai Petani, and
Butterworth. A total of 60 Allied aircraft were lost on the first day, primarily on the ground. No 62 squadron had been moved from Alor Star to Butterworth, and on 10 December it was moved to Taiping. On 10 December, No 21 Squadron RAAF was withdrawn from Sungai Petani to Ipoh, where it was joined on 13 December by No 453 Squadron RAAF. No 453 Squadron had been sent to protect Force Z on 10 December, but arrived after the warships were sinking. On 15 December both Squadrons were pulled back to Kuala Lumpur, receiving replacement aircraft for those shot down or destroyed. Within the first week of the campaign the Japanese had established air superiority. On 19 December the bombers were moved to Singapore, with No 62 Squadron being re-equipped with Hudsons. One pilot—Sergeant Malcolm Neville Read of No. 453 Squadron RAAF—sacrificed himself by ramming his Buffalo into an Oscar of 64th
Sentai over Kuala Lumpur on 22 December. Continued Japanese dominance eventually forced both Squadrons back to Singapore on 24 December, where they were merged until more replacement aircraft could be obtained. No 64 Squadron had run out of aircraft and its surviving ground-crew and airmen were shipped to Burma. RAAF No 1 and No 8 squadrons were amalgamated due to aircraft losses. This left the Allied ground troops and shipping completely open to air attack and further weakened the defensive position. The Genzan Air Group sank
Prince of Wales and
Repulse on 10 December, which also established Japanese naval supremacy. In comparison, the Japanese army enjoyed close air support from the start of the campaign, and sought to capture bases for their air support to operate from. On 25 December, the
Second division of Squadron 5, Royal Netherlands East Indies Army Air Force was deployed to Singapore, contributing to the Allied cause before being recalled to
Java on 18 January. Several Dutch pilots—including
Jacob van Helsdingen and
August Deibel—responded to a number of air raids over Singapore while stationed at Kallang Airport. They claimed a total of six aircraft, particularly the Nakajima Ki-27 Nate, which fared poorly in Malaya. On 3 January 1942, 51 disassembled Hurricane Mk IIBs arrived in Singapore along with 24 pilots (many of whom were veterans of the Battle of Britain) who had been transferred to there with the intention of forming the nucleus of five squadrons. The 151st Maintenance unit assembled the 51 Hurricanes within two days and of these, 21 were ready for operational service within three days. The Hurricanes were fitted with bulky 'Vokes' dust filters under the nose and were armed with 12, rather than eight, machine guns. The additional weight and drag made them slow to climb and unwieldy to maneuver at altitude, although they were more effective bomber killers. The recently arrived pilots were formed into
232 Squadron. In addition, 488 (NZ) Squadron, a Buffalo squadron, converted to Hurricanes. On 18 January, the two squadrons formed the basis of
226 Group. The following day 453 squadron provided an escort of eight aircraft for five Wirraways and four NEI
Glenn Martin bombers, attacking Japanese troops on the
Muar River. All the Martins and one of the Wirraways were lost. No 243 Squadron RAF, equipped with Buffalo fighters, was disbanded on 21 January and 232 Squadron became operational on 22 January, the same day the Genzan Air Group attacked Kallang Airport. 232 Squadron thus had the first losses and victories for the Hurricane in Southeast Asia that day. Most of the bombers were moved to Sumatra midway through January. Aircraft from 36, 62, and 100 Squadrons unsuccessfully attacked the Japanese invasion fleet at Endau on 26 January, suffering heavy losses. The surviving aircraft were evacuated to Sumatra on 31 January. In mid-January, the three Sentai of the 5th Air Corps returned to Thailand to participate in the
Burma Campaign and the 3rd Air Corps turned its attention to the Netherlands East Indies. The last airworthy Buffalo in Singapore flew out on 10 February, five days before
the island fell. The RAAF and RNZAF fighter squadrons left for Sumatra and Java at the beginning of February. It is not entirely clear how many Japanese aircraft the Buffalo squadrons shot down, although RAAF pilots alone managed to shoot down at least 20. Eighty were claimed in total, a ratio of kills to losses of just 1.3 to 1. Additionally, most of the Japanese aircraft shot down by the Buffalos were bombers. ==Advance down the Malayan Peninsula==