Feathers pre exist the Jurassic, by the conventional
means of labeling things "Feathers."

Natural variation.

So, flight came first, then powered flight.

Gliding is a well known mode of transportation
today.

Spread your arms -- and let's call them "Wings"
even if we haven't reached true birds yet -- and
let the wind set you airborne.

POWERED flight becomes useful because it's
a very effective means for not landing in the wrong
place. Like, what if the wind send you out into the
middle of a large lake, or over the sea?

Bad. Scene.

What if the wind takes you 80 miles from your nest,
or straight past your food or, maybe worse, stops
blowing right over things that see you as their food?

So getting into the air is relative easy, when you
began life in the Triassic with a basic bird shape and
already had something that looked like feathers. You
might argue an almost inevitability here. That, sooner
or later, with enough time and random mutations,
something absolutely had to get blown up into the
sky. And once there, LOTS of selective pressures on
POWERED flight.

CONTROLLED FLIGHT.

They had to be able to CONTROL where they were
going, and powered flight would be part of that
control. It would be an element.

It wouldn't have to be perfect. They wouldn't have had
to be able to fly hundreds or dozens or even a few
miles. Not necessarily. Even a few hundred yards or
less of extra distance could have spelled a powerful
advantage...

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