There are several variables that go into a plane getting airborne. Factors such as the size and weight of the airplane help determine how much runway is needed for it to takeoff. The lighter and smaller the airplane the less runway is needed. Planes take off and land into the wind, tailwinds can be dangerous to aircraft. As the aircraft begins takeoff roll the oncoming wind helped by extended flaps on the wings creates lift, when the optimum speed is reached the aircraft will become airborne.