Neil Arnold. Shadows in the Sky: The Haunted Airways of Britain. Stroud: The History Press, 2012. A compilation of, mostly, strange things seen in the sky over Britain. Everything from dragons, fish, battles, and UFOs to, naturally, phantom airships (and ghost aircraft, as in actual ghosts). Lots of interesting details but not much in the way of references.
David Clarke. The UFO Files: The Inside Story of Real-life Sightings. London: Bloomsbury, 2012. Second edition. By contrast, though this is also aimed at a popular audience it's well-referenced, mostly to files held by the National Archives. Indeed, it's published in association with and on behalf of the National Archives, with which Clarke, who lectures in journalism at Sheffield Hallam, has been working closely to secure the release of formerly classified UFO files. Aaand there's good coverage of phantom airships, which is not surprising since Clarke was one of the first people to investigate them seriously.
Paul Dickson. Sputnik: The Shock of the Century. New York: Walker & Company, 2001. As the title suggests, this focuses on the psychological responses to Sputnik in America, more than the technological and political ones (though those are covered too). I remember hearing good things about this book when it first came out but never got around to getting it; today I found it in a bargain bookshop so it wasn't a hard purchase to justify.