fighter aircraft. These attacks usually had little effect, except on morale. The balance of air power soon began to swing in favour of the Israeli Air Force following the arrival of 25 Avia S-199s from Czechoslovakia, the first of which arrived in Israel on 20 May. Ironically, Israel was using the Avia S-199, an inferior derivative of the Bf 109 designed in Nazi Germany to counter British-designed Spitfires flown by Egypt. Throughout the rest of the war, Israel would acquire more Avia fighters, as well as 62 Spitfires from Czechoslovakia. On 28 May 1948, Sherut Avir became the Israeli Air Force. Many of the pilots who fought for the Israeli Air Force were foreign volunteers or mercenaries, including many World War II veterans. On 3 June, Israel scored its first victory in aerial combat when Israeli pilot Modi Alon shot down a pair of Egyptian DC-3s that had just bombed Tel Aviv. Although Tel Aviv would see additional raids by fighter aircraft, there would be no more raids by bombers for the rest of the war. From then on, the Israeli Air Force began engaging the Arab air forces in air-to-air combat. The first dogfight took place on 8 June, when an Israeli fighter plane flown by Gideon Lichtman shot down an Egyptian Spitfire. By the fall of 1948, the IAF had achieved air superiority and had superior firepower and more knowledgeable personnel, many of whom had seen action in World War II. Israeli planes then began intercepting and engaging Arab aircraft on bombing missions. Following Israeli air attacks on Egyptian and Iraqi columns, the Egyptians repeatedly bombed Ekron Airfield, where IAF fighters were based. During a 30 May raid, bombs aimed for Ekron hit central Rehovot, killing 7 civilians and wounding 30. In response to this, and probably to the Jordanian victories at Latrun, Israel began bombing targets in Arab cities. On the night of 31 May/1 June, the first Israeli raid on an Arab capital took place when three IAF planes flew to Amman and dropped several dozen 55 and 110-pound bombs, hitting the King's Palace and an adjacent British airfield. Some 12 people were killed and 30 wounded. During the attack, an RAF hangar was damaged, as were some British aircraft. The British threatened that in the event of another such attack, they would shoot down the attacking aircraft and bomb Israeli airfields, and as a result,