The preface warns that aviation history is unusually vulnerable to secrecy and to organizations hiding failed projects or embarrassing delays. Britain later shortened the closure period on official records from fifty years to thirty, opening files and test reports through the early 1940s to researchers. Those records changed the emphasis of published accounts and corrected some earlier facts and assumptions. Aircraft history therefore depends on archival source criticism rather than on repeating contemporary publicity or performance figures.
Notable Point · 10:42-11:39
Opened government records revise aviation history
Security restrictions and Britain's shorter closure rule explain why later archival research could overturn earlier accounts of aircraft development.