Operation Flax was an Allied air operation during the Tunisian campaign, as part of the larger North African campaign of the Second World War. Flax was intended to prevent air supply between Italy and the Axis armies in Tunis, Tunisia, in April 1943. An equivalent Allied naval effort was called Operation Retribution.

In November 1942, American and British forces landed in North Africa under Operation Torch. Allied thrusts overran Vichy French Morocco and Algeria and advanced into Tunisia. The danger for the Axis powers was now apparent. American forces advancing eastward and the British Eighth Army advancing westward after the victory at the Second Battle of El Alamein, threatened to trap and destroy the remaining Axis forces in North Africa. Reinforcements for the German Afrika Korps, Italian Army and Luftwaffe were dispatched by sea and air. These reinforcements staved off an immediate defeat in Tunisia, the last African region still in Axis hands.

The poor state of the roads and rail lines in Algeria meant Allied forces faced supply difficulties which helped the Axis prolong their defence. The inexperience of U.S. forces was exposed at the Battle of the Kasserine Pass. The growing number and experience of Allied forces squeezed the Axis toward the northern tip of Tunisia. The Royal Air Force (RAF) and Royal Navy operating from Malta took a heavy toll of Axis shipping. Axis supplies were still reaching the Afrika Korps by air and by early April, many Axis personnel were being evacuated by air. Although the Allies held air superiority during the day, Luftwaffe transports were operating with impunity during darkness.

The RAF and the United States Army Air Forces (USAAF) were ordered to attack Axis aircraft by day and night. Owing to bad weather and the lack of intelligence, Flax did not begin until 5 April. Although the Axis put up determined resistance and large air battles took place, the Allied air forces cut the aerial link from Axis-held Sicily and Italy. An air battle known as the 18 April (Palm Sunday Massacre) took place, in which German Junkers Ju 52 transport aircraft suffered many losses over Cape Bon while evacuating (German Army) forces from the Allied ground offensive, Operation Vulcan. Flax continued until 27 April and did great harm to the Axis supply effort. Along with the airlift during the Battle of Stalingrad, Flax was so costly to the German transport fleet that it never recovered.

Background

Strategic situation The Axis campaign in North Africa was characterised by supply shortages. The failure was one of the primary reasons that Generalfeldmarschall (Field Marshal) Erwin Rommel could not defeat the Eighth Army throughout 1941–1942. Rommel, at points, had recognised Malta as a serious obstacle to Axis supply between Axis-held Europe and their forces in North Africa. Malta lay across their lines of communication and, despite the two-and-a-half-year Siege of Malta, it remained a base for Allied naval and air forces to attack Axis supply lines for much of this period. Rommel failed to apply enough pressure on Oberkommando der Wehrmacht (German High Command, OKW) to invade the island, Operation Herkules. Although Malta was mostly neutralised as an offensive base in mid-1942, later that year the Allied offensive from Malta became increasingly effective. The Axis defeat at the Second Battle of El Alamein and the Allied landings, Operation Torch, in Western North Africa, threatened to crush the Axis from east and west. The Germans sent reinforcements to Africa through Vichy-held Tunisia but by the start of 1943 they were suffering increasing shipping losses to Malta-based forces. Some respite was won for the Axis when the Allies lost the "Run for Tunis" in part owing to rapid German reactions and the difficulty in supplying their armies through the poor Algerian infrastructure. By early 1943, the Axis had numerical superiority in aircraft; 690 to the Allied 480.

The campaign from Malta caused chronic supply shortages in Africa. By April 1943, the Allied armies had pushed the Axis forces to the northern tip of Tunisia, near its capital Tunis. Despite the desperate situation, OKW continued to send reinforcements and supplies to the besieged Axis forces by air. To prevent prolonged resistance, the Allies, now aware of the German supply timetables through the use of British Ultra, began an aerial offensive to cut the link. The operation was due to begin in the last week of March 1943 but bad weather over Tunisia meant that it was delayed until 5 April.

Axis supply The Axis situation in the air, on land and at sea was gradually deteriorating. Axis supply ships had suffered many losses between Cape Bon and Sicily, 67 per cent of which were to Allied aircraft. Theo Osterkamp was appointed (Fighter Leader Sicily) to fly over the area. On 7 April 1943, the organisation was given 148 fighters for these operations. The Luftwaffe reorganised its forces in Tunisia, Hans Seidemann was appointed Fliegerkorps Tunis (Flying Corps Tunisia) with three commands, (Flying Leader Tunis), Mitte (Middle) and Gabès, after its headquarters' location. Siedmann had the equivalent of 12 (12 Groups) and maintained around 300 fighters until mid-April. The German fighter defences also benefited from a rudimentary radar supported early-warning network.

(Major General) Ulrich Buchholz, the (Wing Commander) of KGzbV 3, was appointed (Air Transport Leader II, Mediterranean Sea) on 15 January 1943. His forces were organised under the Naples-based KGzbV N ( or Naples) and the Trapani-based KGzbV S; KGzbV S had to make two missions a day, KGzbV S only one. The formations would be 80 to 120 aircraft strong. Operations were to be flown at only , arriving around noon to operate during the Allied "lunch" period. The units—operating mostly the Junkers Ju 52—brought in daily and the giant Messerschmitt Me 323s brought some with their smaller numbers. The logistical effort was made using Indian prisoners of war, who helped unload supplies. The operational method usually involved escort fighters picking up the formation en route. Only one fighter for every five transports was made available owing to shortages. The Naples units were met near Trapani and on the return leg fighters, including Bf 110 , escorted them home. The end of the airlifts at Stalingrad and in the Kuban allowed the number of Axis transport aircraft to reach 185 by 10 March. By the beginning of April, it rose to 426. The force flew much needed ammunition and fuel to the Axis armies in Africa.

Allied plan

James H. Doolittle commanding Northwest African Strategic Air Force (NASAF) was ordered to formulate an air interdiction campaign and named it Operation Flax. Flax called for Allied fighters to intercept the aerial convoys over the Sicily–Tunisia strait. Allied units were also briefed to carry out attacks against Axis airfields in Tunisia and the overcrowded staging fields in Sicily. They were also ordered to carry out anti-shipping sweeps. Flax was an operation which was unlikely to work more than a few times, as shown by the relative impunity with which the surviving Axis air transports operated at night after the operation had begun. The flight time across the Strait of Sicily was so short that aerial interception could be made only with precise intelligence. The Germans understood this but did not know that their communications had been compromised and were being read by Allied intelligence. Ignorant of their intelligence leaks, they operated by day. Since their enemy had the option of flying by night, and the weather conditions were not ideal, the Allies delayed Flax until the most German transport aircraft were in operation so that the blow would be as great as possible. Allied intelligence used information from Y-stations to decide when to begin.

The plan included coordinated attacks on Axis airfields carried out by Boeing B-17 Flying Fortress groups to tie down Axis fighters. Medium bomber units operating the North American B-25 Mitchell would fly sweeps over the Gulf of Tunis. They were to be joined by Lockheed P-38 Lightning heavy fighters which were also detailed to sweep the area. The presence of the B-25s would allow the P-38s to operate in the area without raising the Axis suspicions. It would seem as if they were there to escort the B-25s, rather than to attack Axis air transports. Supermarine Spitfire units would sweep the straits further north, catching any enemy aircraft that evaded the P-38s. More B-25 and B-17 units were detailed to bomb Sicilian airfields to catch transports on the ground. The USAAF 9th Air Force was detailed to send its Consolidated B-24 Liberator bomb groups against airfields in and around Naples in this capacity as well. On 2 April Doolittle's superiors, supreme commander of all Allied Air Forces in the Mediterranean, Arthur Tedder and commander of Allied Air Forces in Western North Africa Carl Spaatz, decided to wait for the next suitable window to launch the offensive.

Order of battle

Allied The Allied order of battle involved all the main commands in the area. The Supreme Allied Air Force Command was the Mediterranean Air Command (MAC) under Air Chief Marshal Arthur Tedder. Below the supreme command were the sector organisations, the Northwest African Air Forces (NAAF) commanded by Carl Spaatz. Directly subordinated to Spaatz was the NASAF under James H. Doolittle. The second command was the operational/tactical force, the Northwest African Tactical Air Force (NATAF) under Air Marshal Arthur Coningham.

Axis

Martin Harlinghausen commanded Fliegerkorps II (Air Corps II), which controlled Luftwaffe operations in Africa, as part of Luftflotte 2 (Air Fleet 2). Subordinate to Fliegerkorps II were seven Kampfgeschwader (Bomber Wings). Several Jagdgeschwader (Fighter Wings) were also available in support. The Luftwaffe had the following forces available in April 1943

II. Fliegerkorps Kampfgeschwader 54, with Stab., I., II., IV (Erg) I./Kampfgeschwader 1 was attached. Kampfgeschwader 76, with Stab., II., III. Kampfgeschwader 77, with Stab., I., II., III. Kampfgeschwader 26, with III. Kampfgeschwader 30, with II.

Jagdfliegerführer Sizilien, Theo Osterkamp Jagdgeschwader 27, with II. Jagdgeschwader 53, with 3 Staffel (Squadron) Zerstörergeschwader 1, with Stab., II., and III. Nachtjagdgeschwader 2, with II.

Fliegerführer Sardinien (Flying Leader Sardinia Wolfgang von Wild) Kampfgeschwader 26, with Stab., I., II. Jagdgeschwader 53, with 9 Staffel

Fliegerkorps Tunis Hans Seidemann 1.(F)/121 Jagdfliegerführer Mitte Jagdgeschwader 53 Schnellkampfgeschwader 10, with III. (III./SKG 10) Sturzkampfgeschwader 3, with II. (II./StG 1) Schlachtgeschwader 2, with 8 Staffel (Panzer), (8 (Pz)./SchG 2) Minensuchgruppe 1, with 4 Staffel 2.(H)/14

Fliegerführer Afrika Walter Hagen Jagdgeschwader 77, with Stab., I., II., III. Jagdgeschwader 51, with II. Schnellkampfgeschwader 2 4.(H)/12

X. Fliegerkorps X. Fliegerkorps Alexander Holle: Jagdgeschwader 27, with III. Lehrgeschwader 1, with Stab., I., II., IV (Erg) Kampfgeschwader 100, with II. Stab SAGr 126, with 2 Staffel./SAGr 126 and 2.(F)/123

Lufttransportführer II, Mittelmeer Lufttransportführer II, Mittelmeer (Commander, Air-Transport Mediterranean Ulrich Buchholz): KGzbV Stab Neapel (Transport Group Naples), with II./KGrzbV 323 and KGrzbV 800 KGzbV Stab Sizilien (Transport Group Sicily), with I., III., IV./KGzbV 1, KGrzbV 106, and KGrzbV 600 Lufttransportstaffel 290 [LTS 290] (Transport Squadron 290) Savoia Staffel (Savoia Squadron)

Regia Aeronautica 54° Stormo CT (54th Fighter Wing) [CT: Caccia Terrestre (Land Fighting)] 7° Gruppo CT ( 7th FG) 16° Gruppo CT (16th FG)

American operations

Closing the straits