If you get in an unrestored military aircraft from about 1980 back, most of them had ashtrays. I flew in a T-34 that was built in the 50s with a restoration that brought everything up to like-new and original. It had an ashtray in the back seat. The owner had a no smoking sticker on the top of the ashtray.
There was a C-131 at the CAF Camarillo for a number of years that had an ashtray on the glare shield for the pilot and copilot, one of each side. The slot was big enough for a cigar.