In this operation emerged some serious difficulties. The Yugoslav authorities delayed the take-off of the Spitfires due to a $1 million debt. Another reason for the delay, which at some point seemed like a sabotage, could have been the Yugoslav striding on a slippery path between the two Super-powers. The IDF agent in Geneva suggested changing the country for refueling to Bulgaria. However, the Yugoslavs eventually made their move and on the 28th of September six Spitfires left Czechoslovakia . Out of the six airplanes only three of them arrived in Israel, one of them crashing on the runway and the other two were forced by insufficient fuel to land in Rhodes, where under British pressure the Spitfires were confiscated and the pilots released after interrogation. As a result of the interrogations the USA and Britain learned all they needed about the "Velvetta”, and was immediately withheld by Belgrade. Luckily when the IDF was about to launch more operations on the Southern front, the negotiations with the Bulgarian government were completed and a new route for the Spitfires was ready.

The Israelis were shocked by the Bulgarian demand to charge 10,000$ for each landing. At the end the Yugoslav government softened and on the 8th of December reopened the Podgorica airfield. On the third week arrived ten out of twelve Spitfires (two crashed due to bad weather). By then Operation Assaf was completed and Operation Horev was in full swing. Until the 1st of February 1949 the Israeli Air Force had six serviceable Avia S.199s and sixteen British XI Spitfires out of the 84 purchased. More Spitfires were shipped; two major consignments arrived in Israel in February and March 1949. The last ship left the port of Gedynia in January 1951.
At some point the Czech offers and helpfulness went further, in May 1948 proposed to sell Israel tanks , artillery and an ambitious training program for Israeli gound troops and pilots. The training began in May, it was planned for approximately a hundred flight cadets which would start the training in Olomouc. For those who would qualify, an advanced course was held in the Czech Air Academy in Hradec Kralove. By the 21st of May, after only nine days of training, five pilots were qualified and rushed back to Israel to fly the first assembled Avia S.199s. The elementary course consisting of twenty Israelis, from which only 13 recieved their "wings", was withheld due to the outrageous price which the Czechoslovak Government was charging. For Israel this course in particular have not been essential, since the IAF had more trained personel then airplanes to fly.

One Czech-Israeli project which particulary alarmed the Western inteligence was the, so called, Czech Brigade . This unit consisted of Jewish members of the "Free Czechoslovakia", which fought with the British Army during WWII. On August the 15th the Brigade started its training at four bases; Libava, Milovice, Velka Strena and Straz pod Ralskem. This program had some enbarrassing consequences, when some of the soldiers demanded a proper salary for their service in the IDF.

Conclusion
The Czech military aid during 1948 was highly improvised. Some of the operations have not been carried out as planned, and some not at all. Israel used the Czech aid not because she leaned towards Communism, but because she was fighting for its survival.
The value of the Czech assistance to Israel's military strength in 1948 can be simplified in to three categories; a) small arms, which were by far the most important of all; b) 84 airplanes from which only a few took part in the Israeli war effort, but took a major part in the demoralization of enemy troops; c) various military services, including military training and technical maintenance.
The price for the Czech help was outrageously high, and Israel paid, since it was essential for the survival of the young state.