Answer:
Upward force is lift.
Downward force is gravity.
Thrust act towards left.
Drag act towards right.
Step-by-step explanation:
The forces acting on the airplane are:
1. Downward force which is due to Earth's gravitation and hence gravitation force acts in the downward direction.
2. Air applies a force in the upward direction in order to make the airplane float in air. This force is called lift force as it lift the airplane in the air.
3. Forward force acts on the airplane which is thrust force which causes the airplane to move forward.
4. The air resists the motion of the airplane and hence applies a force in the backward direction known as drag force.