45 years ago:

http://www.museumofflight.org/747

You probably should have gone with 46 years ago: https://upload.wikimedia.org/wikipedia/commons/1/11/Concorde...

What was your point? Here's a computer from 1965:

http://www.columbia.edu/cu/computinghistory/a10.jpg

Not all technology is increasing at the same rate. Adoption is another problem. Take this bullet train from 1964. Still won't find that in America.

http://cdn.gaijinpot.com/wp-content/uploads/sites/4/2014/10/...

Given your example, I thought you were talking about aircraft, so the diminishing returns in the recent 50 years seemed salient.

Nope, we were talking more about the ability to generate electricity for an electric plane, right? Battery technology, or something else that can deliver electricity.

Of course, 50 years from now we'll have commercial scramjets:

https://en.m.wikipedia.org/wiki/Scramjet

So, progress will be made on many fronts.

Battery technology isn't progressing at anywhere near the rate of computer technology.