No Novelização oficial por Dean Devlin, é explicitamente confirmado que a nave-mãe está de alguma forma fornecendo energia remota (sem fio) para os navios escravizados, incluindo os caças e navios da cidade.
“If we can plant the virus in the mother ship, it would then be sent
down into the city destroyers and the attack ships like this one.
Okun told us that this ship’s power was coming directly from the
mother ship, so that must be true of the large ships, as well.”
Uma vez destruídas com sucesso a nave-mãe, as "arraias" simplesmente caem no chão.
They’d stayed in the air dogfighting with the last remaining attackers
until the gray stingrays had started losing power and falling out of
the sky. Apparently, they had only limited reserves of onboard energy.
Isso também explica por que o navio no Novo México foi encontrado em condições tão primitivas:
Like hundreds of flights before and after it, the ship had conducted
several hours of research and observation. It was only moments away
from completing its mission when the parent ship was suddenly
threatened with discovery and bolted away.
The scout ship had wandered further than it should have and now lay
behind the curve of the earth, preventing the energy flowing from the
parent craft from reaching its engines.