The airplane cockpits I've read about have multiple screens, with knobs selecting the function of each screen (and which of the redundant flight computers control each screen), so a failed screen can be replaced by selecting its function on another screen. This makes more sense (and is simpler) than carrying a replacement screen (which would be dead weight most of the time) and designing a hot-swap mechanism (which would be yet another potential point of failure).

While your plane is falling from the sky?