Missiles, just like planes, still use most of their energy to not crash into the ground.

The point was that this current design won’t be enough energy to keep a heavy vehicle aloft, but it could be enough to propel something that can passively stay airborne.

Except you need missiles to go much faster than ion thrusters can go. 11 mph is enough for someone to shoot down your missile with a rifle.

At 11 mph they could outrun it on foot.

Prepare to engage enemy . . . bogey’s airspeed not sufficient for intercept. Suggest we get out and walk

Anti-missile defense provided by strong gusts of wind.

s/rifle/rock/

"We've fired the missiles, sir"

"Excellent... when do they hit?"

"According to our calculations... ohhh about 6 weeks from now"

Revenge is a dish best served cold.

I was thinking how Musk could do that. Launch some tungstan rods into a highly eliptical orbit, small thruster + control pack on them to adjust their orbit when required. When it's out at say 300,000k+ fire the engine for a few seconds, adjusting the orbit so it will crash into the chosen target a few days from now. The high apogee means not a lot of power to change orbit to collision, and almost impossible to detect. It would likely appear to be an asteroid hit.

I’ve looked at this idea myself. At current cost per kg to LEO launch and kW/kg solar, even if you could totally ignore reaction mass (I dunno, invent a ramscoop for van Allen belts or something), it only becomes cost competitive with dynamite after a few years.

Dynamite doesn't come with a delivery mechanism though, which might change the equation a little.

You may like Heinlein's "The Moon is a Harsh Mistress".

It's rumored that the US military has a "Rod of God" satellite. No way to confirm its existence of course.

That would certainly raise the level of Bitcoin blackmail.

I think his guy is in that Tesla Roadster in space.