Transonic flight occurs at speeds close to the speed of sound, typically between Mach 0.8 and 1.2. The challenges involve dealing with shock waves that form as airflow transitions from subsonic to supersonic speeds, leading to issues such as increased drag, stability problems, and potential structural stress on the aircraft.

One approach is contouring the aircraft's shape, particularly the wings and fuselage, to minimize shock wave formation and their impact. For example, using swept-wing designs helps delay the onset of shock waves. Additionally, employing supercritical airfoils can help manage shock waves more effectively by allowing smoother airflow over the wings.

CFD is crucial for simulating airflow and predicting how an aircraft will perform under transonic conditions. By using CFD, engineers can visualize shock wave formation, pressure distribution, and potential areas of high drag or instability, allowing for better design modifications before physical testing.

Wind tunnel testing and flight testing are essential methods. Wind tunnels that can simulate transonic speeds provide data on aerodynamic performance and shock wave behavior. Flight testing, although expensive, is the definitive way to validate aircraft behavior in real-world conditions and to gather data on performance, stability, and control.

Ensuring structural integrity involves using materials that can withstand the stresses associated with transonic flight, such as high-strength composites or advanced aluminum alloys. Additionally, thorough fatigue testing and incorporating design features that distribute stress can help maintain structural integrity.

Common issues include drag divergence, where drag increases rapidly near the speed of sound, and control surface effectiveness reduction. Mitigation strategies include designing supercritical airfoils to manage drag, using control surface balancing techniques, and employing advanced flight control systems to maintain stability and performance.