Not exactly airspace then...
On the matter of masks a QF Flight attendant for National Jet just lost her unfair dismissal case. Being a FA or pilot and claiming a medical exemption would be a tricky process as most medical conditions that would allow you an exemption from mask wearing would make you also unsuitable to be a pilot or FA as well.
"Jessica Watson of Brisbane, accused National Jet Systems, which is part of the Qantas Group, of unfair dismissal after she was told she would have to undergo an independent medical examination to support her claim of being unable to wear a mask."
www.theaustralian.com.au