The Deal & Execution
The leaders of the Yishuv, already in the spring of 1947, intended to purchase arms in order to improve their defenses. In July 1947 the Chief of the European branch of the Jewish Agency, Dr. Moshe Sneh, paid a visit to Czechoslovakia and was surprised by the sympathy towards Zionism and by the interest in arms export on the side of the Czech Government. Sneh met with the Deputy Foreign Minister Vladimir Clementis, who succeeded the non-Communist and definitely pro-Zionist Jan Masaryk . Sneh and Clementis discussed the possibility of Czech arms provisions for the Jewish state. Masaryk gave his approval, but still there were certain obstacles: first of all it was still unclear what course the Palestinian issue would take at the UN, also the Czech Government was willing to sell only to a sovereign nation. However, the UN Assembly resolution of the 29th November ended the Czech's watchful waiting.

Ben-Gurion sent Ehud Avriel to Paris where he contacted two commercial agents of the Czech Zbrojovka. After that Avriel qualified to meet the people at the top of the Czech Government he was asked to obtain for himself the guise of a sovereign government, such accreditation was bought from Ethiopia at an earlier stage. At this point there were no further obstacles to meet General Ludvik Svoboda, the Minister of National Defense, and signing the first contract on the 10th January 1948. On the same occasion Masaryk slipped a massage to Avriel which said: "the more you buy the less will go to the Arabs". This note may support the theory that the real reason for the Czech military support was mainly commercial, and not a Soviet master plan of taking Israel over. There were four possible routes to transport the arm deliveries in to Palestine via Communist countries; a) the Northern route: via Poland and the Baltic Sea, b) the Southern route: via Hungary, Yugoslavia and the Adriatic Sea, c) via Hungary, Romania and the Black Sea, d) by air, via Yugoslavia to Palestine. According to Avriel the shipment should take approximately a month, but it took more over two months.

However, the first contract included 200 MG34 machine guns, 4,500 P18 Mauser rifles and 5million rounds of 7.92 mm ammunition. This transport was delivered by a chartered "Skymaster" airplane. Avriel was concerned that from that point there could be 3-4 weekly flights, but the Americans thought otherwise and the chartered airplane was forced by the FBI to return to the USA. The day was saved by the arrival of the first shipment which anchored in Beit Daras on the 3rd April. These arms came just on time to launch "Operation Nachshon". The next shipment arrived only at the end of April and the next one on the 25th of May. By the end of May the IDF absorbed as much as 20,000 Czech rifles, 2,800 machine-guns and over 27 million rounds of ammunition. Two weeks later additional 10,000 rifles, 1,800 machine-guns and 20 million rounds of ammunition arrived. By October 1948 the IDF absorbed 46,751 rifles, 6,142 machine-guns, of two types MG34 and ZB37, and 80 million rounds of two types were brought from Czechoslovakia. From May onwards the IDF could equip every new recruit with a personal weapon, every infantry section with a machine-gun and many IDF battalions obtained medium machine-gun support.

Avriel, once he knew that the Americans are preparing to interdict the export of airplanes of any kinds, began to negotiate with Prague regarding the acquisition of "Avia S.199"s .
The Czechoslovak Economic system was going through changes of nationalization, which caused minor delay in the negotiations, but General Ludvik Svoboda, the Minister of National Defense, was kind enough to remove them. The first "Avia S.199" contract was signed on April 23, which included 10 airplanes. A month later another 15 were purchased, bringing the number of airplanes up to 25 with an intention to purchase more .

An old-new problem was facing the Haganah people; How to get the airplanes to Israel? Shipping was one of three possible ways just that the Haganah could not afford to wait until the airplanes would have arrived. So they had to think of something else, flying them from Czechoslovakia to Israel required refueling on the way. The maximum range of these airplanes was approximately one-quarter of the distance from Czechoslovakia to Israel, which made the entire operation exceedingly dangerous. The third option was the dismantling of the Avia's and flying the parts to Israel. This task could have been done with a Skymaster or C-46. The C-46 was unfortunately available only in the third week of May and needed one refueling enroute. The possible places to refuel were Sicily, Rhodes and Corsica. Landing there, except Corsica, until mid-June, incurred he risk of confiscation both the of the plane and of the equipment.

However, the first Avia S.199 arrived in Israel on the 21st of May, carried on board a Skymaster which landed at Ekron AFB together with a teem of Czech technicians. In the meanwhile nine C-46s arrived and joined the airlift called "Operation Balak". On the evening of May 29th, with only four assembled aircraft, Israel's new fighter arm went into action for the first time . Flown by Lou Lenart, Modi Alon, Ezer Weizman and Eddie Cohen, the four S.199s took off from Ekron to try and halt the fast advancing Iraqi and Egyptian forces near the city of Isdud (later Ashdod). Two Avias were lost in that mission. The next day, the remaining two airplanes took of and attacked an Iraqi column near Tul Karem hitting an Iraqi Brigade Command vehicle, but another S.199 was lost leaving General Remez with only one operational Avia S.199 until the beginning of the first truce. One the 3rd of June, the remaining airplane shot down two Egyptian Dakotas which tried to bomb Tel Aviv. Up to the beginning of the first truce 11th of June, 11 Avia S.199s arrived in Israel. From the end of May the "Balak flights" went up to seven a week and the pace of delivery of Avias up to three a week.

Since the Avia airplane was a great disappointment, due to its immense technical problems and difficulty of maneuverability, the IDF gave in a last chance July during the ten days fighting. There after there were barred from such tasks as air-fight or ground strikes. The tasks for the remaining Avias were confined to escorting ground troops and scouting missions. Operation Balak ended on the 4th of August 1948.

In the meantime Avriel was trying to persuade the Czech government selling British XI Spitfires. On the 26th of August the Czechs agreed to stop selling Avias, and instead sell to Israel 50 second-hand Spitfires at a reduced price . In Israel, the availability of these airplanes was viewed as an indispensable condition for launching the new IDF offensive. And again the question of delivery raised in the IDF headquarters. Since the Czechs no longer dared to renew such air-lift as they did with the Avias, and the IDF's experience with dismantling airplanes was a bad one, they had to find another way of bringing them to Israel. At the same time it was clear that the shipment of the Spitfires would not allow them to arrive in time for the IDF's planned forthcoming offensive. The idea of self-flying of some of the planes arose once again. This time to decrease the risk of confiscation of the Spitfires the fuel tanks were expanded to such capacity that only one refueling would be needed enroute. The refueling was planned to happen at the airfield of Podgorica, in Southern Yugoslavia. The planes were expected to arrive on the last drop of fuel to Israel. Twenty-two Spitfires were flown in this way; this was called the Operation Velvetta.