I've heard that the reciprocating engine that we all use is about 30% efficient. In other words, about 70% of the stored energy in a volume of fuel goes out the tail pipe. If we used the oil and coal to make and store fuel more efficiently and developed the infrastructure accordingly, we'd have something.
I believe electrical generation from fossil fuels is around 30% efficient too, so that doesn't help. In fact, if you then convert from electricity to an intermediate form like hydrogen, it's actually worse... the only real use for hydrogen as a power source is for a means of storing renewable energy by, say, using solar power to split water either electrically or thermally.
Interestingly I was reading about a British hypersonic aircraft design from the 60s at the weekend and that included comparative drawings of a kerosene version vs hydrogen powered... the hydrogen version was enormous in comparison. Lockheed also considered hydrogen for the Blackbird but again from what I remember the huge fuel tanks and difficulty of refueling convinced them that relatively conventional fuels were the way to go.
What you can do with a fossil fuel power plant is to exploit the waste heat in a useful manner, for example by heating houses or greenhouses. That's harder to do in a plane or a car, though electric cars are going to have to work pretty hard to warm up the passengers on a typical -40 winter's day here, while fossil-fueled cars can just use the waste heat to do so.