Aira was never much for flight; that is why she ended up with her boring job mindleslly sorting letters to be delievered by others. Her mother went MIA a while ago, but whatever. Her dad was a mailman so he wasn't around much, Aria learned to not need people. She didn't mind the company, but she faired better alone.
Leaving dragonroost island might be nice, but flight just wasnt her thing and here she had a routine. Day in and day out, she could always expect the same thing. Occasionally someone would hit on her, that would always make her day, but she would never let them know.
If her pride didn't get in the way maybe she would admit that she was poor at flying, uncommon.. unheard of really among the Rito and she WOULD leave. Aria would opt for her boring life instead of admit needing help.