I flew a plane the last few days that had the most worthless cupholders I've ever seen. It was a single metal panel with about a 2.5" circular hole in it. Too small for a mug and nothing to hold up anything that fits into the hole.A coffee mug that actually fits in the cup holders.
I fly a PC 12. I have the official PC12 travel coffee mug. It is too big for any of the FOUR cup holders in the cockpit. SighI flew a plane the last few days that had the most worthless cupholders I've ever seen. It was a single metal panel with about a 2.5" circular hole in it. Too small for a mug and nothing to hold up anything that fits into the hole.
I'd say it probably depends on what they fly - We have very little room for storing anything in the cockpit, so I've seen some interesting carriers/containers used by other pilots. Other types don't all suffer from that.