What is the main purpose of pre-treating an aircraft before snowfall?

The main purpose of pre-treating an aircraft before snowfall is to create a protective layer against ice. This pre-treatment typically involves applying a de-icing fluid that forms a barrier on the aircraft's surfaces. This barrier prevents the accumulation of snow and ice, which can be crucial for maintaining the aircraft's performance and safety during flight. If ice forms on the wings or control surfaces, it can significantly impact aerodynamic efficiency and the handling characteristics of the aircraft. By effectively preventing ice from bonding to the aircraft, pre-treatment helps ensure safe operations during and after snowfall conditions.

The other options, while they touch on relevant topics regarding aircraft maintenance and performance, do not capture the primary intent of pre-treating before snowfall. For instance, enhancing aerodynamics is important but secondary to the need for ice prevention. Fuel consumption and rust prevention are also critical considerations, but they are not directly related to the immediate necessity of dealing with ice formation during snowfall.