Sound waves in air are longitudinal waves, while waves in coaxial cables, known as Transverse Electromagnetic (TEM) waves, are transverse. The distinction lies in how the waves propagate: sound waves require a medium like air, whereas TEM waves can propagate through the electromagnetic field in the coaxial structure. The discussion highlights the misconception that air is trapped between the conductors in coaxial cables, clarifying that it is not necessarily the case for high-quality cables. Understanding these differences is crucial for comparing the two types of waves effectively. This comparison underscores the fundamental principles of wave propagation in different mediums.