Designing and drawing plans on...

[B Sharp]

All this takes me back to the where I started my apprenticeship in 1970. Drafting film and drawing pens, T-squares and set squares and proper drawing boards - I still have them all and use them occasionally. The best thing was that when the electricity went off they still worked!
Brian.

[Dave Cooper]

Yes, I still use my son's old drawing board and instruments. CAD is great where you need high accuracy of fit and repeatability.

For airflow design work, I still prefer pencil and paper and imagining the air flowing over a surface. I do have the benefit of a model wind tunnel (10 %) at home to check the results - not always as I imagined it but good fun anyway...
Dave