The mechanism: US-China air travel isn't a free market — it's a fixed pie divvied up by government order. The Department of Transportation allocates a hard cap of weekly "frequencies" between US carriers under Title 49 international economic authority, and every increase to that cap only happens after State Department and DOT officials negotiate new capacity bilaterally with Beijing's aviation authority. The current cap is climbing from roughly 50 weekly US-China round trips toward 100 by the end of 2026 under a new bilateral understanding — DOT's largest reopening of transpacific capacity since the pandemic gutted the route map. Each time the ceiling moves, DOT runs a show-cause docket where carriers file competing applications for the new slots, and history shows the incumbent with the biggest existing Beijing/Shanghai footprint and the most idle widebody capacity usually wins the allocation fight. That's not a one-time headline — it's a recurring regulatory event traders can actually watch on regulations.gov.