Unless you tie your interia cancelling engines into the “ether” to lower your fuel costs.... then you can reduce the fuel needed to move, but you will have a medium like air to move around in...
WHOOSH
You also have to limit your set speed since there is no atmosphere to provide a constant drag and your velocity would continue to increase as your main engine operated. Keep it running too long and you will run out of air and or fuel before you could brake and return. Unless your speed was already too high and you were then on the long way out and not coming back.