From November that year until September 1944 the squadron supported the advance of the Allied ground forces through western New Britain and the north coast of New Guinea by attacking Japanese positions, providing fighter protection for recently established beachheads, and escorting Australian and United States bombers.

78 Squadron was reduced to a cadre after it returned to Australia in December 1945, but received new aircraft in 1946 and undertook training exercises until being disbanded in April 1948.

78 Squadron began to receive its P-40N Kittyhawk fighters from 2 August 1943, and conducted training with these aircraft until early October.

10 (Operational) Group, a mobile formation established on 13 November to support the planned Allied advance along the north coast of New Guinea.

[3] These operations were undertaken to support the landings conducted by American forces at Arawe on 15 December and Cape Gloucester on the 26th of the month.

78 Squadron also escorted RAAF and United States Army Air Forces (USAAF) bombers on several occasions.

78 Squadron during January supported the Australian Army forces engaged in the Markham and Ramu Valley – Finisterre Range campaign.

[8] The squadron was mainly used to escort Australian and USAAF bomber and transport aircraft in February and early March, but it also conducted a small number of ground attack sorties.

78 Wing's fighter pilots, who believed that the American officers in charge of the air effort in New Guinea were assigning Australian units to unimportant tasks.

In reality, all Allied fighter units recently arrived in New Guinea were initially tasked with escort missions as part of a 'probationary' period.

78 Wing moved to Cape Gloucester in New Britain to replace the USAAF's 8th Fighter Group, which was being transferred to Nadzab.

78 Wing struck Japanese positions in New Britain and nearby Garove island in co-operation with United States Navy PT boats.

78 Wing received orders to move again, this time to support Operation Reckless, the American landing at Hollandia in western New Guinea.

[12] The main party of the squadron departed Cape Gloucester on 17 April bound for Tadji airstrip on the mainland of New Guinea, and its Kittyhawks arrived there on the 24th of the month.

78 Squadron operated from the Hollandia beachhead; owing to food shortages in the area the pilots arrived with rations for four days loaded in their aircraft.

[13] On 15 May the unit moved permanently to an airfield near Hollandia, from which it escorted USAAF bombers and formed part of the force protecting the US Army landings at Wakde on 17 May and Biak on the 27th.

[19] This was the squadron's sixth move in nine months, and the intensive effort needed to pack and unpack stores on each occasion caused widespread fatigue among airmen and ground crew.

[24] The squadron also struck airfields on the Bomberai Peninsula as well as Japanese shipping in the easternmost islands of the Netherlands East Indies (NEI) during the last months of 1944.

These operations were undertaken to support the American landings in the Philippines, which began in October, and often involved lengthy flights.

The squadron flew 267 sorties in January during which its aircraft fired 77,000 rounds of machine-gun ammunition and dropped 153,630 pounds (69,690 kg) of bombs.

78 Squadron ceased operations from Morotai to prepare to take part in the invasion of Tarakan, an island off the east coast of Borneo.

78 Squadron disembarked at Tarakan on 6 May, but it took much longer than had been anticipated to repair the island's airfield and the unit was unable to recommence flying operations until 18 July.

During this period the squadron's ground crew worked with Australian Army engineers to build roads, and some personnel spent time on the front line.

[27] The squadron conducted its final combat operation on 9 August, and was still based at Tarakan at the time the Japanese Government's intention to surrender was announced on the 15th of the month.

[32] Following the armistice the squadron undertook leaflet dropping and reconnaissance sorties until November, when the Kittyhawks were flown to Australia.

The remainder of the unit's personnel arrived at Sydney on 12 December 1945 on board the British aircraft carrier HMS Glory.