I would go the Scum and Villainy way. If you play a 'monster' race, replace your starting ability with a 'Xeno' one. Player and GM should work on it together. Quote from the rules:
If you want to play a xeno with unique abilities, replace your starting ability with the following: “Xeno: You may spend stress (0-2) to perform an inhuman feat only members of your species can do.”
Reflavouring is always an easy and safe method. Someone else have already done the balancing. And if you don't faind exaclty what you are looking for you have examples to work off.
That being said... For example getting into the baron's mansion undetected through the third story balcony is the same conflict regardless if you are flying or climbing the walls like a gecko. You have position and effect for balancing. Flying may be Desperate (easy to spot/shoot down) and Great for example.