Airport metal detectors are susceptible to metals, including orthopedic metal implants inside the body. As a result, people with metal implants, such as those used to save limbs and patients' lives, often face more significant and frequent inconveniences, with more invasive security checks becoming commonplace.

Metal is strictly regulated at airport security primarily because it is a key component in the manufacturing of weapons (such as knives and guns) and the triggering mechanisms for explosive devices. Security scanners, including traditional walk-through metal detectors (WTMD), work by creating an electromagnetic field; when a metallic object passes through, it disrupts the field and triggers an alarm. By requiring passengers to remove belts, coins, and jewelry, security can "clear" people of concealed threats. In 2026, while advanced 3D CT scanners and millimeter-wave "body scanners" can see through clothing to identify both metallic and non-metallic objects, the presence of large metal items can still cause "shielding" or artifacts on the screen that hide dangerous items. Furthermore, certain metals are restricted in checked baggage—such as large quantities of lithium-ion batteries or pressurized canisters—because they pose a significant fire or explosion risk in the unpressurized or inaccessible cargo hold of the aircraft.