Math is the fundamental tool of aeronautical engineering. Whether modeling shapes, designing on a computer, checking stresses and strains, calculating fluid dynamics or determining areas, math is the root of all these activities. Math is the fundamental principle behind almost all engineering, and there are few important functions that can be accomplished without it being used in some form.
Lift is the fundamental concept of aviation. It requires an understanding of Bernoulli's equations, how to calculate linear velocities and area. All of these actions are very math-intensive. Some require simple multiplication, but others require solving equations with calculus. Without being able to mathematically calculate a lifting force on a wing, it would be impossible to determine if a design for a plane would allow it to fly.
The heavier a plane is, the more lift is required for flight. Therefore, aerospace engineers look for light weight materials to use in plane construction. However, the materials must still have the required strengths to deal with the loads and stresses that are a part of flight, take-offs and landings. Math plays a vital role in determining material strengths and their reactions to various stresses and strains.
Moving air is treated as a fluid. Fluid mechanics is a critical study for aerospace engineers. It helps them to understand the forces that air will exert on a moving object and how they can impact a vehicle in flight. Fluid mechanics is very math-intensive and requires an understanding of calculus and linear algebra.
Planes do not get funded unless they are economically feasible. Math skills help engineers understand costs, what trade-offs can be made and the future implications a decision may have on the cost of a project. Math helps an engineer formulate the economic justification for any recommendations to a project that require a financial outlay.