"Commercial Aviation Is Working Closely with the U.S. Military on FT Fuels..."
"The U.S. Department of Defense is in the forefront of activities on FT synthetic fuels, driven mainly by concerns for energy security. In 2006, the Air Force conducted a test flight of a B-52 using a 50 percent blend of FT synthetic fuel with conventional jet fuel. The DoD is planning to purchase 200 million gallons of synthetic fuel for additional field testing. Their goal is to establish the requirements for operational use of FT fuels. The DoD has set an ambitious goal of using 50 percent synthetic fuel by 2016."
The interesting fact of this particular reference is that liquid fuels made from coal are being put into passenger jets from all over the world at Johannesburg. That would presumably include some from US carriers.
The main point, though, isn't that air carriers from other countries are using coal liquids in their planes - they know and we now know that jet fuel made from coal is technically just fine.
The main point is that they are willing and able to pay for that jet fuel made from coal. It must not be much, if any, more expensive than jet fuel made from petroleum; else, with South Africa now free of trade sanctions and embargoes, the international carriers could insist that petroleum-based fuel be imported for their use so that they could save money.