: Besides, they're talking about conventional rocket technology. The PoA, as we
: saw in Reach, used it's own power to escape the atmosphere. Part of the
: same drive system that can go faster than the speed of light .

: Prophet of Regret in Halo 2 came down with a Supercarrier to Earth. They have
: no problem getting back out to space and they're much larger than the
: class of ship the PoA was. Or, as we saw in Halo 2 (also Halo 3: ODST), if
: you're OK with a little collateral damage, you could just teleport out
: of the atmosphere.

: *shrugs*

The Autumn can't travel faster than light in that sense. And those giant thrusters it has are for sublight travel. Remember that gizmo welded to the Pelican in Reach? That's what allows the frigate to go Slipspace.

No amount of 'thrust' will allow you to go fast enough to exceed the speed of light. General Relativity explains why that's impossible.

What Slipspace drive does is allow you to punch a hole into another dimension, emerging in real space at another location in a time shorter than it would take light to travel there in normal space. That's why it's referred to as 'faster than light'.