In this world I’m dabbling with, the dominant species is a race of six limbed humanoid with two wings on its back slightly below the shoulder blades. They are very slender (“BMI” is between 17 & 18) with the wings having evolved as a pair of secondary limbs. Finishing them off is a pair of tail planes evolved from the fibula. The wings have what looks like a second pair of Pectoralis major under and behind the usual ones. Their bones are hollow and filled with methane, they also have a methane bladder which they use both for buoyancy and to spew fire.
They are primarily predators and have limited flight ability. Powered flight is limited to a minority of the population who have what’s considered to be genetic defects with surface symptoms similar to asthma and narcolepsy. This “disease” affects around one in every 1,000 and having it will only slightly increase the chance of your child having it. The wings are bat-like and of the broad soaring variety (like eagles or vultures). The blood is amber coloured from the Coboglobin pumping through their veins.
The larger cities are built to encourage updraft for the inhabitants to fly on. The higher levels are more expensive to live in (for obvious reasons) and are generally built near large bodies of water as fish is their primary food source. The rooftops are commonly public spaces which you can glide from to catch one of the very popular steam trains. As powered flight isn’t an option, rail travel is very popular as aircrafts are still in their infancy with the general tech level being that of a 1920-30s Europe.
Is this humanoid dragon realistic the way I’ve imagined it?