Operations began for the invasion of Denmark and Norway on 9 April 1940 and continued until the capitulation of the Norwegian army on 10 June 1940. The British had evacuated their last forces from the Narvik area on 7 June 1940, and the next day the Royal Navy aircraft carrier Glorious and two escorting destroyers were sunk by the German battlecruisers Scharnhorst and Gneisenau. Glorious took with her the remaining aircraft of the RAF’s 46 (ten Hurricanes) and 263 (ten Gladiators) Squadrons, which had miraculously landed on the ship from their Norwegian bases on 7 June; eight of the Hurricane pilots were lost and all 10 Gladiator pilots from 263 Squadron as well. Scharnhorst was badly damaged by a torpedo hit and limped into Trondheim; British naval and land-based air attacks continued against her there and later in Stavanger until 21 June 1940, thus ending the aerial action related to what the Germans had named Unternehmung Weserübung. This codename translates as Operation Weser (River) Exercise, which can perhaps be taken as sarcastic, bearing as it does allusions to a mere military river crossing.
German fighter units employed in this operation were limited to I/ZG 1 (Me 110s) and one Staffel of I/LG 2 (briefly) over Denmark, and I/ZG 76 (Me 110s) and II/JG 77 (Me 109s) in Norway; II(J)/186 (Me 109s; later renamed III/JG 77) was posted into the Scandinavian theatre on 2 June 1940.3 Despite the invasion of Denmark being generally described as bloodless, in fact two Danish fighters did get off the ground and both were shot down by Me 110s and their pilots killed; one claim was awarded to Stab I/ZG 76’s Hauptmann Wolfgang Falck.
On 9 April 1940, poor weather conditions played havoc with planned German paratroop drops and airborne infantry landings over southern Norway; six of an original eight Me 110s of 1/ZG 76, who were supposed to have landed after the initial paratroop attack to refuel at Oslo-Fornebu airfield, ended up capturing it basically single-handed as the first Ju 52 transport finally landed. 1/ZG 76 had arrived first over Fornebu but were bounced by nine Norwegian Gladiators from out of the sun, losing two Me 110s and both crews; in return two of the Gladiators force-landed on the airfield and were set on fire on the ground by the remaining six Zerstörer. The latter had another aircraft written off when an already damaged Me 110 made a crash-landing on Fornebu. A Sunderland flying boat was also claimed by this Staffel during the day. Other Me 110s of I/ZG 76 en route to cover airborne landings at Stavanger lost two of their number and both crews to the dreadful weather along the way.
I/ZG 76 (operating mostly from Stavanger and Trondheim) and II/JG 77 (flying mainly from Kristiansand, Stavanger, Trondheim) rapidly became established on southern Norwegian airfields, and most air combat was against British bombers (including Coastal Command aircraft) flying from the UK, plus Royal Navy carrier-borne aircraft. Accredited fighter claims totalled 57: eight Wellington heavy bombers; 12 Hampden medium bombers; eight Blenheim light bombers; 14 Hudson patrol bombers; five Skua and two Roc carrier aircraft; two Sunderland flying boats; one Danish Fokker; five Gladiators (two Norwegian, three British). Most victories went to II/JG 77 (36) and I/ZG 76 (14), with one Hudson to I/ZG1 over Denmark, five victories to the Zerstörerstaffel of KG 30 and one to II(J)/186. German bombers claimed one Hudson for a grand total of 58 confirmed victories for the campaign. They also accounted for most of the aircraft of 263 Squadron RAF, flying from a frozen lake at Lesjaskog – on 25 April 1940, the day after 18 Gladiators had taken off from a carrier, 13 of them were destroyed by bombing and strafing of the German bombers on the lake, two of them after force-landing with combat damage from the bombers. The remaining five Gladiators were rapidly decimated by lack of repairs and maintenance plus combat damage, and by 29 April the squadron was withdrawn. They were back on 21 May 1940 with 18 new Gladiators; of these only three were lost in aerial combat, with two pilots killed and one wounded. I/ZG 76 claimed a Gladiator on 27 May and two more on 2 June 1940. Others were damaged in combat and two lost in crashes. The remaining 10 Gladiators flew out and landed on the carrier Glorious on 7 June 1940 and were lost when she was sunk next day. The 18 Hurricanes of 46 Squadron RAF arrived from a carrier on 26 May and operated from Bardufoss in northern Norway. They had many combats, mainly with German bombers, but also with Me 110s of I/ZG 76; a major action occurred on 29 May 1940, when nine Hurricanes took on 26 He 111s of Kampfgruppe 100 and KG 26, escorted by elements of I/ZG 76. Although two He 111s and one Me 110 (crew POW) were shot down, three Hurricanes were lost and two pilots killed; at least one of the Hurricanes fell to I/ZG 76. By the time 46 Squadron was withdrawn, eight Hurricanes had been either shot down, lost in accidents or damaged beyond repair, and the remaining 10 landed on the aircraft carrier Glorious on 7 June 1940, as already related.
II/JG 77 flew into Danish airfields on 9 April 1940, moving to southern Norway three days later. On 13 April, in a combat against Hampdens, of which they were credited with eight against six actually lost, five Me 109s were also shot down with four pilots killed, an inauspicious start to their long stay in Norway. Better success attended their efforts against carrier aircraft attacking the damaged Scharnhorst in Trondheim harbour on 13 June 1940, when four 4/JG 77 Me 109s together with four I/ZG 76 Me 110s fought against a formation of 15 carrier-borne Skuas, the JG 77 pilots claiming four. Six days later, when UK-based Beaufort torpedo bombers attacked this patched-up vessel on its way from Trondheim to Stavanger, another six victories were credited to II/JG 77. At this stage in their history, this Gruppe was saddled by a commander to whom it was difficult to relate; on 30 May 1940, in a drunken state, Hauptmann Karl Hentschel threatened some of his pilots with a drawn pistol, which they were able to take from him soon afterwards. He was replaced in September 1940 after a delegation of the Gruppe’s officers went to higher authority. An unusual ‘Luftwaffe Hauptmann’ arrived in the middle of April 1940 and joined II/JG 77 for about four to six weeks, flying operationally; he was none other than Obergruppenführer (SS rank of full general) Reinhard Heydrich, the chief of the Intelligence and Counterintelligence services of the SS, and later a leading organiser of the death camps and the Holocaust. Soon after his arrival he wrote off his Me 109 on take-off and was lucky to get away with it. Soon after this crash he is reported to have refused the award of the Iron Cross 2nd class (EK 2), awarded for combat missions flown, due to having written off his own aircraft. However, many photos show him wearing both EK 2 and 1, plus the Frontflugspange (Front Flying Clasp) in Silver (awarded at 60 operational missions), so the refusal could not have been permanent. In June 1941, after flying briefly with I/JG 1 over the North German coast, he joined the JG 77 Gruppe again, this time without permission, and flew some operations on the Russian front, and after a short time was shot down by flak and crashed in no-man’s land from where he was fortunate to be rescued unharmed.
II/JG 77 stayed in Norway till 9 November 1940, when they were transferred to the Channel Front. After 21 June 1940 a further 45 victories were credited to them, including a notable success on 13 August 1940 as ‘Eagle Day’ was launched in the Battle of Britain. 12 Blenheims of 82 Squadron, thinking to take advantage of the Luftwaffe’s attention being elsewhere, raided Aalborg airfield in Denmark, where 5/JG 77 had just been transferred. 11 were shot down against 15 claims by the fighters and one by anti-aircraft (AA). The leading ace of II/JG 77 in Norway was Feldwebel Robert Menge, who was awarded 13 victory confirmations. II(J)/186 (the later III/JG 77), which had arrived in Denmark on 2 June 1940 and moved to Norway two days later, only claimed two victories in their time there. At the end of July 1940 they were transferred to the Berlin area, relieving I/JG 77 who moved to the northern coastal areas of Germany. After II/JG 77 was notified on 13 August 1940 of re-equipment with captured Curtiss P-36 fighters from France due to a shortage of Me 109s, which were reserved to replace expected losses over England, 12 P-36s were finally supplied in mid-September; they remained with the Gruppe till the end of October, when Me 109s were received in their place.