What the Germans did is gasify coal first.  They developed the Lurgi gasification process (which is the granddaddy of gasification if you ignore water gas generators) to produce synthetic gas, which is a mixture of H2 and CO.  Using that, they could produce methane or use Fischer-Tropsch synthesis to produce diesel (easy) or gasoline (harder).  You can still buy Lurgi gasifiers from Germany, though there now are other types.

Fischer-Tropsch is the only GTL process in large-scale industrial use today, AFAIK.

The Graf Zeppelin, the Hindenburg's older sister, was fueled with gasified coal. Blimps are an energy efficient form of transport of cargo that DOESN'T absolutlely, possitively have to be there overnight.
The Zeppelins had the one flaw: Hydrogen lifting gas. Of course, a mix of rust and powdered aluminium didn't help. Helium came from Texas gas wells and was stockpiled by us. For helium blimps, there is a limited amount of helium with none left in the ground since we Yanks had the monopoly.

While blimps are energy-efficient, you can't replace the planes with them due to lack of new helium reserves. We already had a full depletion cycle!

In fact, according to the EIA "by the end of WWII, Germany 's nine indirect and 18 direct liquefaction plants were producing approximately 4 million tonnes of liquids per year, satisfying 90 percent of Germany' s total petroleum consumption".

The direct coal to liquids process was used to produce high quality gasoline, while the FT process yielded diesel fuel. The 1931 Nobel Prize in Chemistry was awarded to Friedrich Bergius for the development of the direct process.

I don't know of anybody using his process nowadays.

Looked it up om Wikipedia.  The process looks close to the H coal process that Exxon was examining once upon a time.  Looks like the Germans started from a syngas feedstock to get the required hydrogen.