[JtD]

zipper, some planes had negative stability, too. There are may different types of stability, and planes can be perfectly save and even still fairly easy to fly without fly-by-wire with some sorts of negative stability. Check out the "spiral mode" - meaning a plane in straight and level flight trimmed for such has a tendency to lower one wing an go into a spiral, which will usually cause a descent and may result in a crash. This was common with single engined fighters of the era, and also common in game. It's not a problem for the pilot, unless he's unconscious, because this takes several minutes to become dangerous and is easily corrected with normal flying.

But in combination with CO poisoning or malfunctioning oxygen equipment or disorientation after a black out under high g or flying in clouds with poor instrumentation or iced up windows or ..., this may be deadly.

Directional stability of the fighters back then was also pretty poor compared to modern standards. It's one thing that is most commonly found in pilot comments when folks used to a modern day Cessna try out a warbird for the first time.