Fun statistic: the Wright Bros' first flight was shorter than a 747 is from tip to tail. (their 4th flight was a bit longer, though)
The whole thing was designed on paper, with hordes of draftsmen drawing every single section, detail, etc.
I’m always impressed at how complex things could be with no CAD
https://arstechnica.com/science/2013/04/how-nasa-brought-the...
Early in my career I had an “Asimov moment” firsthand - I was an intern working on a project to instrument an industrial facility with better sensors, etc. The whole place was dependent on a 100 year old machine that just did its thing every day with only minor maintenance and repairs. (I think the power source has been swapped out a few times) The manufacturer was long defunct and the plan was to keep the thing running indefinitely. Pretty sure it’s still there!