The first entry is always the pin's source. Overall confidence is a weighted average of how firmly each reference supports the start and end times used above; a reference counts half as much for every 180 days older than the newest.
Happened as dated, per en.wikipedia.org: "The 747’s first flight took place on February 9, 1969, and the 747 was certified in December 1969."
Adds the prototype’s name, City of Everett, the departure from Paine Field and the one hour 15 minute duration, none of which the source[1] article gives.
Trade-press anniversary account confirming the 9 February 1969 first flight from the Everett factory.[1]
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