zlacker

There actually is a clean line between flying and not flying. And that's when the lift generated is greater than the pull of earth's gravity. The fact that it "feels" weightless gradually doesn't change the fact that if lift<weight then the plane is not flying. If lift>weight, plane is flying. There is no "semi flying". If it's already airborne and lift becomes less than weight, then it stops flying and starts gliding.

The lift is an emergent behavior of molecules interacting (mostly) with the wings. But there is a hard clean cutoff between "flying" and "not flying".

>>vright+(OP)
Of course, but the cutoff I one of perception more than physics. The airplane is “not flying” right up until the lift generated is infinitesimally more than the weight of the aircraft. Likewise, during “flight” there are times when the lift is less than the weight, during descent. So the line seems clear but it is a matter of degree. The aircraft is not doing anything fundamentally different during the takeoff roll than during flight, it is all a matter of degree. There is no magical Change in physics or process.

>>K0balt+rM
"straight and level flight implies that lift equal to weight == flying too