U.S. secondary sanctions are beginning to isolate Iranian airlines.
The UAE suspended Iranian-airline flights. Oman stopped accepting them. Other routes across the region have been disrupted.
China remains a major test of how far U.S. pressure can reach.
The U.S. is trying to ground every Iranian airline on September 23.
The leverage: the US dollar.
Treasury Secretary Scott Bessent says airports that provide Iranian airlines with fuel, landing services or ticketing risk being cut out of the U.S. dollar system.
Will airports around the world comply?