[Aardwolf]

0 and O look almost exactly the same in the font, is the distinction of these not important on flight screens?

[eviks]

Another research project needed to uncover such basics

[froh]

wouldn't you think the better UI choice is to simply avoid situations where you can confuse O and 0 (and l and 1 and I) ?

[Aardwolf]

No, I don't think that's a better choice at all, making two characters look the same is the worse choice, having to design something to avoid situations of two identically looking characters being together sounds much clunkier, than having the characters not look the same in the first place. Plus, airport codes, radio frequencies, airspace zones, GPS coordinates, etc... have numbers and letters.