Not just removing, but also preventing a build-up of snow and ice on the wings and tail of an airplane is crucial for a safe take-off. ... Snow and ice on these areas in essence changes their shape and disrupts the airflow across the surface, hindering the ability to create lift.

What happens if you don't deice a plane?

The ice alters airflow over the wing and tail, reducing the lift force that keeps the plane in the air, and potentially causing aerodynamic stall—a condition that can lead to a temporary loss of control.

Why planes need to be de iced before lift off?

“Smooth airflow assists in the production of lift, and if ice accumulates on the wings, it distorts the smooth, laminar flow of air over the wing, and lift is reduced,” Manders told AccuWeather. “If lift is reduced too much, there's the potential of an aerodynamic stall.”