The essential components of an airplane are a wing system to sustain it in flight, tail surfaces to stabilize the wings, movable surfaces to control the attitude of the plane in flight, and a power plant to provide the thrust necessary to push the vehicle through the air.
If a flight takes a plane across several countries, it passes through various ACCs, each monitored by different air traffic controllers who give instructions to the pilot as needed.
While most of this passes behind the plane, some of it swirls upward, which can reduce lift. Modern airplanes account for this via their upturned wingtips, which help minimize the effect these swirls of air can have on the plane’s ability to maintain lift and smooth forward flight.