Leslie Douglas Jackson

Flight Lieutenant Jackson (second from left) with fellow pilots of No. 75 Squadron in Port Moresby, 1942

Completing his service with No. 21 Squadron in November 1941, Jackson was again posted to No. 23 Squadron in Australia.[2][4] In March 1942, he joined No. 75 Squadron in New Guinea as a flight lieutenant, under the command of his brother, known as "Old John".[7] Operating P-40 Kittyhawks, the unit quickly became engaged in the defence of Port Moresby, one of the crucial early battles in the New Guinea campaign.[8] As one of No. 75 Squadron’s flight commanders, Jackson took part in a surprise raid against Lae airfield on 22 March. Five Kittyhawks led by John Jackson attacked and destroyed a dozen Japanese planes on the ground, while four others including Les provided protective cover above; he survived an encounter with three Mitsubishi Zeros that saw two of his fellow pilots shot down. Two days later he recorded his first aerial victory when he intercepted and destroyed a Zero escorting a force of bombers towards Port Moresby.[4][7]

On 6 April, Jackson was forced to ditch his aircraft on a coral reef, but made it to shore with the aid of a life jacket that his brother John dropped to him.[9][10] In the following weeks, Les accounted for another three Japanese aircraft shot down. On 5 April, he was attacked from behind by a Zero while firing on bombers front-on, but was able to turn the tables on the Japanese fighter and shoot it down in flames. The next day he went head to head with more Zeros, damaging two before being forced to ditch on a reef with a smoking engine; once down he scrambled out of the cockpit and danced on the wing to let his comrades know he was safe.[11] Jackson shot down his third victim on 17 April. He achieved his fourth victory against another Zero on 24 April,[12] to become the highest Australian scorer in the Battle of Port Moresby.[11] On 28 April, John Jackson was shot down and killed while leading the interception of a Japanese raid; Les took over command of No. 75 Squadron the next day.[4][12] On 30 April, the squadron was recalled to Australia to refit and regroup; Jackson flew one of its last remaining serviceable aircraft to Cairns, Queensland, on 9 May.[12]

Squadron Leader Jackson (right) with Wing Commander "Sam" Balmer (left), commanding No. 100 Squadron, and Squadron Leader "Bluey" Truscott (centre), commanding No. 76 Squadron, Milne Bay, 1942

Following re-equipment in Australia, Jackson led No. 75 Squadron back to New Guinea, arriving at Milne Bay on 25 July 1942 in company with another Kittyhawk unit, No. 76 Squadron.[13] During the Battle of Milne Bay, Jackson’s squadron was engaged in air defence against Japanese raiders and offensive strikes against convoys and other targets in support of Australian ground forces. On 25 August, the Kittyhawks launched an attack on enemy barges at Goodenough Island that resulted in all seven vessels being set on fire without the loss of any aircraft.[14] The next day, Jackson personally led two of his unit's five concerted strafing assaults on the main Japanese convoy approaching Milne Bay. On 27 August, he and a fellow pilot each claimed a Zero; the Japanese fighters had been focussing on machine-gunning one of their own aircraft that had crash-landed following combat with a USAAF B-26 Marauder, presumably to prevent it falling into Allied hands, and were 'bounced' by the Australian pilots.[4][15] His victory made Jackson an ace, the first from the RAAF in New Guinea.[16] By 28 August, Japanese troops were threatening to overrun the RAAF airfield at Milne Bay, and the Kittyhawk squadrons were ordered to withdraw to Port Moresby for one night. Returning to Milne Bay the next day, Jackson’s plane developed trouble and he had to ditch on the coast; with the help of New Guinea natives, he reached Port Moresby by boat three days later.[2][15] By 7 September the Japanese had withdrawn their troops from the Milne Bay area; Generals Sydney Rowell and Cyril Clowes both described the efforts of Nos. 75 and 76 Squadrons as "the decisive factor" in repulsing the invading forces.[17]

No. 75 Squadron was redeployed to Horn Island, Queensland, in September 1942, and Jackson handed over command to Squadron Leader John Meehan the following January.[18][19] In recognition of his "courage and leadership" in New Guinea, Jackson was awarded the Distinguished Flying Cross (DFC), which was promulgated in the London Gazette on 26 March 1943.[20][21] Having served in staff positions in Australia during the year, he was appointed wing leader of No. 78 (Fighter) Wing, a component of the newly formed No. 10 Operational Group, in December 1943.[1][22] The wing participated in Operations Reckless and Persecution, the assault on Hollandia and Aitape that opened the Western New Guinea campaign, in April 1944.[22] This was followed by the attack on Noemfoor, commencing in June.[23] Jackson was promoted to acting wing commander in September 1944.[1] Completing his tour with No. 78 Wing in December, he was posted to No. 8 Operational Training Unit, New South Wales, as chief flying instructor.[4] In March 1945, Jackson was awarded a bar to his DFC for "determined and successful attacks on enemy installations and shipping". That June, he took command of Air Defence Headquarters in Madang.[1][24]