On US Air Force fighter jets, magnets made of rare earth minerals that are mined or processed in China are needed to start the engines and provide emergency power.
On precision-guided ballistic missiles favoured by the US Army, magnets containing Chinese rare earth materials rotate the tail fins that allow missiles to home in on small or moving targets. And on new electric and battery-powered drones being adapted by Marines, rare earth magnets are irreplaceable in the compact electric motors.
Bloomberg