[jcrawfordor]

I wouldn't expect it to get deleted for any kind of security reason... but it will get replaced, and possibly faster because there's a defect. Moving object artifacts are undesirable and make the image more difficult to use especially for automation (such as Google's registration). They tend to get knocked out automatically over time as the composition algorithms try to keep a neatly consistent scene. They may even be handled as clouds depending on which methods Google uses to avoid cloud cover. This is the same force that has slowly worked most alignment and registration marks out of Google imagery (for a long time aerial imagery usually contained registration marks etched into the camera optics), although you will still find them especially in areas that are more challenging to register by machine vision (deserts, etc).

Aircraft in Keyhole and Google Earth used to be extremely common before the composition methods improved and more imagery sources became available. You could just about make out the traffic pattern at some airports. You can still find them but they're much rarer today.

[jaytaylor]

Too bad they can't mark a tile (such as this one) to preserve forever from the backend control plane.