As a retired history teacher, little details bother me that would most likely not be noticed by other viewers. And, as I watch episodes of "12 O'Clock High", I am constantly annoyed by the clothing and hairstyles of most of the women on the show. They are clearly 1960s in style...and are radically different than hair of the WWII era. "R/X for a Sick Bird" features one of these 1960s style actresses.
In this episodes, a long spate of mechanical problems begin affecting bombers in Colonel Gallagher's group. Eventually, the problem becomes so severe that it could only mean that someone or some group of people are sabotaging the planes. When Gallagher learns this is also happening to other bomber groups, it's obvious the saboteurs are well organized...and this could mean dead crew members or a dead partisan (Gia Scala) that is supposed to be dropped behind enemy lines in an upcoming mission.
While there were problems with sabotage during WWII, most instances were actually against the Axis powers...though folks sabotaging bombers isn't too far outside the realm of possibility. What did seem highly unlikely, however, is using a B-17 bomber at a means to parachute insurgents into enemy territory. Usually a C-47 or C-46 transport plane would do this because they were designed for such things. Still, like the hairstyles, I doubt if most viewers would notice or care.
Overall, worth seeing but nothing brilliant about this one. So sad to see Scala, however, as she lived a very short and tormented life.