Actually ALL operations to and from foreign countries is regulated by treaties. Some are unrestricted and some are very restricted.
Our treaties between the US and Japan initially only allowed Northwest and Pan Am ( bought by United) and the 2 freight carriers FEXEX and UPS. Additions have been added over the years and the US is trying to allow open skies treaties between the countries. China just allowed additional flights from the US to mainland China Continental and American received them.

So the cargo operators are governed based on the treaty the US has with the country.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car