I found any math I needed to do in a cockpit was easy enough to do in my head or on a notepad. Very analog. The other thing I often use is a stop watch. And thirdly, the only thing I consistently stuff up is time zones. And for that, I can recommend a beautiful analog representation such as this:
https://www.patek.com/en/collection/...ions/5930G-010 - if you have $70k or so to spare that is. :-)