Preceded by the Sherut Avir, the air wing of the Haganah, the Israeli Air Force was officially formed on May 28, 1948, shortly after Israel declared statehood and found itself under immediate attack from its Arab neighbors. At first, it was assembled from a hodge-podge collection of civilian aircraft commandeered or donated and converted to military use. A variety of obsolete and surplus ex-World War II combat aircraft were quickly sourced by various means – both legal and illegal – to supplement this fleet. The backbone of the IAF consisted of 25 Avia S-199s (purchased from Czechoslovakia, essentially Czechoslovak-built Messerschmitt Bf 109s) and 60 Supermarine Spitfire LF Mk IXEs, the first of which, "Israel 1" was locally assembled from British abandoned spare parts and a salvaged engine from an Egyptian Spitfire with most of the rest purchased from Czechoslovakia. Some spitfires were ferried from Žatec base code-named "Zebra" where pilots also received preliminary flight training, while others were transported by sea. Creativity and resourcefulness were the early foundations of Israeli military success in the air, rather than technology (which, at the inception of the IAF, was generally inferior to that used by Israel's adversaries). Many of the first IAF's pilots in 1948 were foreign volunteers (both Jewish and non-Jewish) and World War II veterans, who wanted to collaborate with Israel's struggle for its independence. The IAF's humble beginnings made its first air victories particularly impressive and noteworthy.