I grew up with a Uk version from probably ww1 in my family’s place. Edit. This one https://www.dpvintageposters.com/posters/original-british-wwi-poster-public-

I grew up with a Uk version from probably ww1 in my family’s place. Edit. This one https://www.dpvintageposters.com/posters/original-british-wwi-poster-public-warning-aircraft-observation-chart_10760 https://www.dpvintageposters.com/posters/original-british-ww...