[…] formations were so decimated that, apart from the special air units stationed at Stalino and Makeyevka, the Germans stopped referring to their aircraft as part of a group or squadron, and classified them only as flyworthy or unflyworthy.
Source: wiktionary
With two aircraft riddled with hits and no longer flyworthy, the balance four flights were called off.
Source: wiktionary
Although seemingly complete, even to the non-aviator the craft was blatantly not fly-worthy as parts of the fuselage carried gaping holes.
Source: wiktionary