References 385% CONFIDENCEOverall confidence: 85%How well the pin's source and references back up its dates.Weighted average of how firmly 3 references, the source included, support the pin's start and end times; a reference counts half as much for every 180 days older than the newestShow all pins at 75% confidence or better
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.
- [1]90%youtube.com/watch?v=V6fZStfEefoyoutube.com· Posted Sep 15, 2026· Starts Sep 29, 2016 ✓· 50% of score
DLR's[3] own press release and the EAA both date HY4's first official flight to September 29, 2016.
- [2]80%
- [3]90%Zero-emission air transport – first flight of four-seat passenger aircraft HY4 - DLRdlr.de· Published Sep 29, 2016· 0% of score
DLR's own news release announces HY4's first flight on September 29, 2016 from Stuttgart Airport, the exact aircraft and hydrogen fuel-cell technology discussed in the documentary.
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