The comments regarding aircraft turbine engines are inefficient at cruise have little ground.
At altitude, as the air density drops, the maximum thrust of the engines also drop, so they actually operate at %85-90 N1 at cruise. When an aircraft has an engine failure at altitude, the first thing it does is to DESCEND, as it simply does not have enough power to stay in the air when that high. So yes, jet engines are most efficient at full thrust, and they operate pretty close to that at cruise.
Twin engine fighter jets typically shut down one engine when loitering, as they have enough power to sustain a high (>30000 feet) altitude with one engine operating at military power.
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I think turbine engines will have some use for ground vehicles sooner or later, because by design, they have the potential of operating at a higher efficiency than reciprocating engines. Theoretical maximum for diesel engines is ~%55 and ~%65 for turbine engines, the key differentiator being the compression ratio. It is currently impossible to efficiently scale down turbine engines currently, but I believe that hurdle will soon be overcome.
Lastly, there is one ground vehicle application of a turbine engine that I'd like to mention:
68 tons, 1500 hp, top speed ~85 kph (although governed to 75 kph). Rather thirsty though...