<p>It was tiring and dangerous work, flying belly to the sand, but that task, combined with the methodical advances of the infantry, gradually forced the Germans north in Tunisia. They mounted one last major offensive against raw American troops dug in at Kasserine Pass. It panicked them, and weakened the British and Free French positions on the line of battle. It threatened the airfields at forward operating locations, which were abandoned with the loss of stored gasoline, supplies and some disabled aircraft, all of which were burned or destroyed to keep them out of German hands.
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<p>Everything with wings was thrown into the fray at the Kasserine Pass. Heavy bombers howled by at low altitude to drop their bombs on the German positions. The offensive was broken, and the Germans continued their retreat toward Cap Bon, their only remaining escape route. Tactical air power chased them, and sunk their ships and flamed their supply aircraft on the runs from Italy.
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<p>American fighter units, now on the east coast of Tunis around Sousse, monitored all the air and sea convoys to Cap Bon by radar. Like wolves, they harried the slow-moving ships and planes. On 18 April 1943, they caught a large air convoy of tri-motored Ju 52s on their way back to Italy after having unloaded in Bizerta. Four squadrons of P-40s from the 57th Fighter Group, 9AF, with a top cover of Spitfires, ripped into them. When the 'Palm Sunday Massacre' was over, about 100 transports and 16 of their escort of Bf 109 and Bf 110 fighters had been downed. Four days later, RAF Spitfires and South African Air Force P-40s caught another convoy, this time of giant Messerschmitt Me 323 six-engined transports, and shot down 21 of them. It was the end of German attempts to fly in supplies by day.
