A UPS employee reportedly missed an email from freight forwarder DSV warning that a shipment was subject to U.S. arms export regulations and should not be routed through Hong Kong.
The shipment was sent from Australia to San Francisco and contained an F-35 cockpit canopy and weapons-bay door coated in radar-absorbing material. After a delay, the UPS worker rerouted it through Hong Kong to speed delivery, where Chinese authorities seized the parts.
The incident has prompted investigations by the Pentagon and the U.S. State Department.