Actually this is line number 6 of all 707s built. Delivered originally to Pan Am as N712PA in 1958, it is pictured on taxiway 'Foxtrot' in front of a spring shower, having just arrived on the weekly service from Istanbul.
The Grunau Baby III was a further development of the Grunau Baby IIb with a slightly longer wing and fuselage and the addition of a wheel. Schleicher built a series of 21 from 1951 to 1955 and also Meschenmoser built a series. But many more were amateur built by gliding clubs. D-4303 was built by Schleicher in 1951 and later handed over to the Deutsches Segelflugmuseum at Wasserkuppe.