I had misremembered. It's not for air traffic control, but for aircraft cockpits. It's this: https://b612-font.com/
In particular I suspect that the '()' and '[]' glyphs are far more common in source code and terminal use than in cockpits. I found them far, far too similar. Also there's little distinction between 'O' and '0' , and between 'I' and '|'. Other than those problems, it's mostly fine - 'l' and '1' are usefully distinct, for instance - but the friction from those particular difficulties was enough to make me hate it.
In particular I suspect that the '()' and '[]' glyphs are far more common in source code and terminal use than in cockpits. I found them far, far too similar. Also there's little distinction between 'O' and '0' , and between 'I' and '|'. Other than those problems, it's mostly fine - 'l' and '1' are usefully distinct, for instance - but the friction from those particular difficulties was enough to make me hate it.