Lockheed SR-71 Blackbird: Is Nasa bringing back the retired spy aircraft into service?

The SR-71A Blackbird, which was on display at Nasa’s Armstrong Flight Research Center in California, has disappeared, triggering speculation of its return. While this fastest spy plane holds a unique place in aviation history, experts say restarting the SR-71 programme would be exceedingly difficultUS’ famous fastest spy plane SR-71 Blackbird likely to make a comeback in the skies after nearly 27 years.