explain to flyFlying is a controlled moving through the air by an object. Airplanes are heavier than air so they can fly only in a aerodynamically way.
Thermals helps to ascend, but does not explain the basic principle of aerodynamic flight, because gliders are able to fly without thermals. Even the mere presence of a wing in itself, does not lead to fly. When motion (dynamics - aerodynamics) comes into play, a wing is very helpful. Yes only "helpful". Imagine a motor-driven aerobatic aircraft in a knife-edge flight - the wings in this maneuver supporting no function. If the wings are not essential for flying, then also the airfoil does not give the real answer to the cause of flying. Even with classical semi symetrical profiles controlled reverse flight is possible by some planes.
For the basic principle of flying the elementary laws of nature are relevant. They are universal and always applicable. The laws of nature are applicable for e.g. vehicles, aircraft, birds flying, insects, supersonic missile, model airplanes, helicopters, parachuts or others and not contradict each other.
Introduction ⇐ | ⇒ properties of Air