I never understand why someone in charge of making one specific simple choice, ends up making a remarkable dumb decision. Why, unless you are doing things unethically, would you go for a licensed font? It's not like this is a hard problem to solve more than adequately with open and more accessible alternatives.
Aside from licensing, usability studies show that serif fonts are more legible than sans serif fonts, so I have no idea where they came up with the idea that somehow they're harder to read for people with disabilities when all prior research I'm aware of has shown the opposite.
I vaguely remember something about there being a difference on printed paper vs screens when it comes to serifs. But also, aren't most aircraft controls labeled in something like Futura? I believe the Apollo program and other aerospace studies decided that was the most legible.