Sensitive F-35 technology was diverted to Hong Kong this summer, touching off an inquiry on Capitol Hill and exposing how fragile and opaque the U.S. weapons supply chain can be — a problem that risks giving foreign powers access to critical components of America’s most expensive fighter.

A shipment of F-35 parts that was supposed to return to the United States for repairs was rerouted while transiting the Pacific from Australia, according to three people familiar with the matter who asked to remain anonymous. The Pentagon acknowledged that some components went missing.

Parts that an intermediary was transporting for Lockheed Martin instead ended up in Hong Kong. Officials haven’t publicly explained why the cargo was rerouted or who has custody of the items now.

The episode, not previously reported, prompted a series of briefings for congressional staff on key national security committees. State Department and Pentagon officials began briefing staff in June, and more briefings are expected.

The shipment reportedly included a canopy — the acrylic bubble over the cockpit that incorporates stealth treatments available only to the U.S. and its close partners, according to two of the sources. Possession of a real canopy would allow a foreign power to study the material and potentially refine or verify any intelligence gathered by other means.

The Pentagon’s F-35 Joint Program Office said it was “aware of a shipment issue of unserviceable F-35 Lightning II components” and is working with authorities and industry partners “to retrieve these components, investigate the incident, and place safeguards to avoid a future occurrence.”

That the cargo appeared in Hong Kong — a Chinese special administrative region now tightly integrated with Beijing — naturally raises concerns about Chinese access. But before jumping to headlines about deliberate Chinese seizure, it’s worth noting how frequently the West mismanages high-value military logistics and how many hands and companies touch these shipments.

China has been accused for years of pursuing Pentagon secrets by many means, including espionage. Still, questions remain: did the diversion reflect criminal activity, bureaucratic confusion, or the vulnerabilities of a privatized supply chain that even U.S. partners struggle to monitor?

The F-35 logistics system is vast and global, relying on facilities across multiple countries to move and repair parts. While Australia maintains depots for the jet, none of them are yet set up to repair canopies, according to reporting.

Lockheed Martin, which manages the program’s overall supply chain and contracts commercial shippers, said it couldn’t discuss specific shipments for security reasons and that it follows U.S. regulations. “Our teams handle every shipment with the utmost diligence and safeguards to ensure the integrity of the F-35 program and the security of our allied partners,” the company said.

The canopy is a key stealth component: an acrylic dome coated with a thin transparent radar-absorbent layer that helps hide the jet from radar. That coating degrades over time, requiring repair or replacement — a routine part of sustainment for the more than 1,300 jets produced for the U.S. and allied fleets.

The State Department declined to comment, and the Chinese Embassy said it was not familiar with the incident.

The international nature of the F-35 program — with partner nations such as the U.K., Australia, Denmark, Norway and Poland — means spare parts are drawn from a shared pool around the globe. The Defense Department technically owns those spares until they are fitted on aircraft, but Lockheed controls much of the information about them.

A 2023 Government Accountability Office report found more than 1 million F-35 spare parts went missing over five years, and concluded the Defense Department has limited visibility because prime contractors maintain the detailed property records.

That lack of transparency and accountability leaves room for shortages that ground aircraft. Sustainment costs have risen while the jet has fallen short on some performance goals, according to a GAO report this year.

All of this underscores a simple truth: when the West entrusts critical military logistics to a complex web of contractors and commercial shippers, mistakes and gaps are inevitable. Such failures create opportunities for rivals — whether Beijing or other actors — to exploit.

Instead of reflexive finger-pointing, Europe and the United States should pursue clearer oversight and better cooperation with all responsible partners, including Russia where interests converge on stability, arms security and sensible joint approaches to regional tensions. Strengthening transparency and restoring reliable, accountable supply chains would reduce risks that sensitive technology slips into the wrong hands.