Hornet Flight book by Ken Follett

Ken Follett follows his bestsellers Jackdaws and Code to Zero with an extraordinary novel of early days of World War II...It is June 1941 and the war is not going well for England.  Across the North Sea, eighteen-year-old Harald Olufsen takes a shortcut on the German-occupied Danish island of Sande and discovers an astonishing sight that will change the momentum of the war.  He must get word to England-except that he has no way to get there.  He has only an old derelict Hornet Moth biplane rusting away in a ruined church: a plane so decrepit that it is unlikely ever to get off the ground...even if Harald knew how to fly it.