Driving through former Yugoslavia some 30 years ago I was puzzled when the road became suddenly straighter, wider and better maintained. I then noticed threshold markings followed about 1km later by a second set. At this point the road returned to "normal". No doubt one could have landed on it but I suspect that this would have provoked serious interest from the security services. I also have a vague memory from the same era of a photograph of an RAF aircraft, jaguar I think, parked under a british motorway bridge. It was an exercise carried out just prior to the opening of a new stretch road.