Well I just watched this weeks episode on the DC-3. Again, well done - following the progression from the Boeing 247 to the DC-1/DC-2 (my memory hasn't failed me yet - the DC-1 was a prototype while the -2 was the production version) and how that lead to the DC-3. Mainly stuff I already knew but still interesting with lots of personal touches (interviews with some of the original "air hostesses" from the 1930's were interesting).
I've found the debates about what "airplanes" (or 'aero planes') belong on the list to be interesting (the title does specify "planes", so while I think the Saturn V was the most impressive engineering feat of my lifetime, I don't think rockets or rotorcraft belong on
this list).
Much depends on how one chooses to define the criteria - for example while the Boeing 247 was revolutionary, the DC-2/3 made it work. Similarly (at least in my book), the Comet was revolutionary, but the 707 made it work. Hence the DC-2/3 makes the cut, and I'd rate the 707 above the Comet.
All that being said, the previews indicate next week will be the A380
I'll get some popcorn