Unable to load :(

data-updates.lua, attempt to index local 'acraft', line 399

The if check on line 372 references the normal hovercraft but line 397 and 398 reference the assault hovercraft. Probably why it crashes?
IMHO the if check on line 372 should close on line 393 and then another if block should be opened for the assault hovercraft.

So it should be:

if data.raw["spider-vehicle"]["DMV-acraft-entity"] then
local acraft = data.raw["spider-vehicle"]["DMV-acraft-entity"]
-- code here
end

It might also be mod compatibility since I'm using a lot of mods, let me know if you need a save :)

I addressed this in 1.0.6 just as you said. Also made more clear in the description that the hovercraft this mod supports is from "One More Hovercraft". Thank you for the report!

Thanks, so https://mods.factorio.com/mod/Hovercrafts by Arcani_Victus is currently incompatible with it or does DMV just not add WASD support to their mod prototypes (their entity name is also "hcraft-entity")? Maybe add it as incompatible to the dependencies tab if so?

DMV only changes specific entities by name, so yes if it has the same name, DMV will try to affect it. Any other mod-added vehicle is unaffected by the mod.