[4][5][6][7][8] Flax was intended to prevent air supply between Italy and the Axis armies in Tunis, Tunisia, in April 1943.

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 RAF and the United States Army Air Forces (USAAF) were ordered to attack Axis aircraft by day and night.

An air battle known as the 18 April Palmsonntag Massaker (Palm Sunday Massacre) took place, in which German Junkers Ju 52 transport aircraft suffered many losses over Cape Bon while evacuating Heer (German Army) forces from the Allied ground offensive, Operation Vulcan.

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.

Rommel failed to apply enough pressure on Oberkommando der Wehrmacht (German High Command, OKW) to invade the island, Operation Herkules.

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.

[10][11] 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 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.

[13][14] 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 ships had suffered many losses between Cape Bon and Sicily, 67 per cent of which were to Allied aircraft.

The Naples units were met near Trapani and on the return leg fighters, including Bf 110 Zerstörer, 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.

Allied units were also briefed to carry out attacks against Axis airfields in Tunisia and the overcrowded staging fields in Sicily.

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.

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.

The Luftwaffe had the following forces available in April 1943[18] X. Fliegerkorps Alexander Holle: Lufttransportführer II, Mittelmeer (Commander, Air-Transport Mediterranean Ulrich Buchholz):

[24] The RAF had also been involved in the day's operations; 152 Squadron sent 34 Spitfires to intercept 12 Ju 52s escorted by a handful of Bf 109s.

At Trapani the Germans lost eight aircraft and 40 damaged for the loss of two B-17s to the island's fighter defences consisting of Bf 109s from JG 27.

Battles over the airfields in the afternoon were inconclusive, costing the Axis one Ju 88 from II./KG 26 and the Allies a RAF Spitfire from 232 Squadron.

The British spread their forces more thinly to maintain continuous coverage and on 16 April 13 Spitfires ran into a large formation of Axis aircraft.

[29][30] On 16 April, in a small counter-attack, eight SchlG 10 Fw 190s, escorted by 16 Bf 109s of JG 27 led an attack on Allied airfields near Souk el Khemis.

Soon enough, a large formation of 30 Ju 52s was reported by Allied pilots at an altitude of only 1,000 ft (300 m), flying north east on a return flight.

[42] By early May 1943, only the Italian fighter units and one German Gruppe (I./JG 77), remained as the Axis held on to a narrow strip of African coastline near Tunis.

Allied air superiority was so overwhelming, that Luftwaffe personnel climbed into fighter fuselages, or squeezed into the cockpits of Bf 109s alongside the pilot rather than risk flying in transport aircraft.

Some supply drops were attempted (by II./Kampfgeschwader 1), but most of the remaining signals, FlaK, transport and administrative staff left were captured when the campaign ended on 13 May 1943.