You always adjust your speed to road conditions. Or you maintain the maximum speed for a short time and then get buried ;).
That depends on the plane's glide ratio, air speed, and angle of attack,and on how long it has been falling.It does NOT depend on the plane's weight.
When thrust and drag are equal, the plane's speed remains constant. The forces are balanced, and the plane will maintain its current velocity without accelerating or decelerating. This state is known as "steady level flight."
To maintain course and speed
Consult the aircraft's instructions for the launch configuration for the best glide speed. To launch at and maintain this speed, you may need to specifically trim the aircraft's surfaces.
A plane may stop accelerating due to reaching its maximum speed limit, encountering headwinds that counteract its forward motion, or due to the pilot intentionally reducing engine power to maintain a specific speed or altitude.
The lift force on a plane is equal to its weight when it is flying at a constant speed and altitude. This balance is necessary for the plane to maintain level flight. If the lift force becomes greater than the weight, the plane will climb; if the lift force becomes less than the weight, the plane will descend.
Thrust on a plane is generated by the engines, which push air backwards to create a forward force that propels the aircraft through the air. This forward force overcomes drag to accelerate the plane, allowing it to take off, maintain speed, and climb. Pilots control the amount of thrust to climb, descend, or maintain altitude during flight.
The forces acting on a plane flying at a constant height include lift, weight, thrust, and drag. Lift counters weight to keep the plane in the air, and thrust is provided by the engines to overcome drag and maintain speed.
Propulsion is what keeps a jet in the air. Otherwise the plane has to fall down. Propulsion keeps the air always flowing over the wing which in turn keeps the plane afloat.
It depends on the aircraft, the speed and the maneuver that the plane is doing. If they are doing loops or rolls, no, centrifugal force will hold them in place. If the plane is 'flying' upside down, a maneuver that is possible in some aircraft, yes, gravity will cause them to fall.
The plane doesn't fall from the sky because its lifting force lifts it in the air.