We have thoroughly documented that airplanes can fly, and have flown, on liquid fuels made from Coal.
Among our reports attesting to that fact have been several concerning the flight by WV's then-Congressman Jennings Randolph, not long after WWII, from Morgantown to Washington, DC, in a small airplane powered by Coal liquids; and, most recently, one revealing the approval by international aviation authorities for commercial use of South Africa Synthetic Oil Limited's, SASOL's, 100% Coal-based jet fuel.
And, we have made reports on work at Penn State University, with another soon to follow, concerning their development of Coal-based aviation fuel.
We have also recorded that the US Department of Defense has been actively developing Coal-based liquid fuels, primarily for the Air Force. That, aside from their development, with the help of contractors such as United Technologies, of liquid fuels synthesized from Carbon Dioxide for use by Navy ships at sea.