1. Some other aspects of aerial existence

2. Using friction to stay up in the air
Thripps
Feather-like wings
Very small body size
Spiders
Secretion of long threads

3. Origins of flight

4. Genesis Wings--Cooling devices
Aquatic insects emerged on to rocks, probably associated with thermoregulation, possibly to escape predation
Lateral outgrowths of thoracic body wall acted as an airfoil as drafts of air flowed over the “proto-wing” lift was produced which caused the creature to be air-borne
Natural selection favors the survival of those creatures having such surfaces which then evolved into “real” wings.