Mediterranean

Illustrious left Scapa Flow in August and arrived in the Mediterranean by September. Orr became an ace in the following months, claiming seven aircraft shot down out of 30 claimed by his squadron.^[2][3] Orr's victories included a CANT Z.501 flying boat on 2 September and on 4 September off the Dodecanese he shared in the shooting down of a Savoia-Marchetti SM.81 bomber.^[7] One of the first larger missions Orr took part in was providing the fighter cover for the Fairey Swordfish attack on the Italian fleet at Taranto. Other missions included attacks on German army positions at Bardia, bombing Tripoli in Libya, and attacks on the Rhodes airfields.^[2][3] Orr was also awarded his first Distinguished Service Cross (DSC) for his service during these missions.^[8]

On 10 January 1941, Orr and Sub-Lieutenant Graham Hogg observed two Savoia-Marchetti SM.79s making a torpedo bombing run on Illustrious; after a long chase they managed to shoot one of them down.^[9] The Italian planes, however, had just been a diversion, because at the same time three squadrons of Junkers Ju 87 dive bombers from Sturzkampfgeschwader 1 and Sturzkampfgeschwader 2 arrived over the carrier.^[9] The Ju 87s were circling the fleet at 11,000 ft (3,400 m), out of the range of the navy's anti-aircraft guns. They then targeted the carrier, diving down and hitting her six times. Orr, down at sea level and out of ammunition, climbed up through the carrier's anti-aircraft barrage in an attempt to disrupt the dive-bombers' attack.^[4] With Illustrious damaged and unable to land her remaining seven Fairey Fulmar fighters, the aircraft were ordered to land at RAF Hal Far on Malta.^[10]

From RAF Hal Far, 806 Naval Air Squadron provided air cover for Malta and Illustrious which was berthed in the Grand Harbour at Valletta, under repair. On 5 February Orr shot down a Junkers Ju 88 that was bombing the city.^[10] In total, flying in the defence of Malta, Orr added five more victories to his record and was awarded a second DSC.^[4][11] The damage to Illustrious could not be repaired at Malta so she was sent to the United States for repairs. Meanwhile, 806 Naval Air Squadron remained in the Mediterranean, joining another Illustrious-class aircraft carrier,HMS Formidable.^[3]

On board Formidable, Orr's squadron provided the fighter cover for her Fairey Albacores and Fairey Swordfish during the Battle of Cape Matapan in March 1941 and the bombing of Tripoli.^[3] Orr shot down a Ju 88 during this time.^[3] Another victory followed on 21 April. Flying over Tripoli, Orr and Sub-Lieutenant Graham Hogg forced a Dornier Do 24n flying boat down with its engine on fire. Each time it tried to take off again the pair carried out another attack until it eventually sank.^[12] When Formidable was put out of action by German Ju 87 dive bombers, 806 Naval Air Squadron was again sent to operate from land. This time they were based at the naval Dekheila Airfield near Alexandria in Egypt and, at the same time, were re-formed with Hawker Hurricane fighters. In June, the squadron took part in operations against the Vichy French in Palestine.^[2]

United States

In August 1941 Orr, having spent 18 months on operations, returned home and became a flying instructor at RNAS Yeovilton. A year later in August 1942, he was sent along with 80 officers and men to the United States to form 896 Naval Air Squadron. The squadron was equipped with Grumman Martlets at Norfolk, Virginia and then joined HMS Victorious.^{[4][nb 2]} A shortage in American aircraft carriers resulted in the lending of Victorious to the United States Pacific Fleet where she was known by the alias USS Robin and her aircraft were repainted with American markings.^[4] Orr was prevented from joining them in the Pacific when he contracted polio in March 1943. He spent 10 weeks at Pearl Harbor in an iron lung before making a complete recovery and was later sent home to Britain.^[4]

804 Squadron

On his return, Orr feared he would be grounded but in August 1943 he was given a new command—804 Naval Air Squadron, which at the time was land based at RNAS Eglinton (HMS Gannet) in Northern Ireland and equipped with the Grumman Hellcat.^{[13][nb 3]} With his new squadron Orr joined HMS Emperor, an American built Ruler-class escort carrier, in December. Emperor was involved in convoy escort duties and in the spring of 1944, the squadron started attacking German shipping off the Norwegian coast.^[2][4]

The presence of the German battleship Tirpitz in Altafjord in Norway was a constant threat to the Arctic convoys and required the Royal Navy to retain a large aircraft carrier force with the Home Fleet to conduct operations along the Norwegian coast and to provide cover for these convoys. In March 1944 the fleet formed a large strike force in an attempt to destroy the Tirpitz in Operation Tungsten.^[14] The force included the fleet carriers HMS Furious and HMS Victorious, which were tasked with carrying the main strike force of Fairey Barracudas and Vought F4U Corsairs, while the main fighter force was provided by the escort carriers Emperor, which was equipped with Grumman Hellcats, together with HMS Searcher and HMS Pursuer, carrying Grumman Wildcats.^[15]

Orr, who was in command of the second strike group, remembered: "Upon arrival over Tirpitz it was found that the smoke screen generated by the Germans had ridden half way up the mountains on either side of the Kaafjord. Each flight attacked their pre-briefed gun sites once it was clear that no enemy fighters were in the area. The Hellcat proved itself to be an excellent gun platform on this mission."^[15] For his part with this operation, Orr was awarded the second Bar to his DSC.^[2] A mixed formation of 18 aircraft from 804 and 800 Naval Air Squadron on 14 May, led by Orr, attacked shipping near Vikten Island and, along with Lieutenant Blyth Ritchie, he shot down a Heinkel He 115 floatplane.^[16] At the same time he also shared in the destruction of two Blohm & Voss BV 138 flying boats and two more Heinkel floatplanes, for which he was mentioned in despatches.^[3]