Early postal links with Israel - first flight mail from Bulgaria: 20 V 1948 registered cover from SOFIA Bulgaria to TEL AVIV, franked 220 Leva & tied by 2x strikes of the local Sofia-Airmail postmark + Bulgarian airmail etiquette & registry handstamp; carried by the CSA Czech Airways flight which landed in HAIFA on 26 May (Sde Dov near Tel Aviv closed as of 15 May due to the Egyptian aerial bombardment in the War of Independence and all civilian air traffic was routed to Haifa) & backstamped next day arrival.
CSA was until 29 May, when Air France service began, the only foreign airline flying to Israel. This cover was carried on the 5th incoming CSA flight since the first one on 16 May, here carrying mail from Bulgaria, Czechoslovakia, Hungary, Poland, Romania, Switzerland, Yugoslavia and the Soviet Union; the mail was sorted in Haifa and then dispatched. Opened roughly at top but very fine postal markings & historic cover with arrival proving date, predating the restablishment of airmail to Bulgaria on 9 June.