Actually, there is gravity. It shows when people call to their death from orbit.Guickly scanning the thread, didn't see anyone else mention gravity yet. This was really my main concern in the demonstration, there was no kinda gravity whatsoever, the ships just stuck to air and spun around looking silly. I mean, that constellation landing in the beginning, you could practically see every individual key press when the pilot aligned the ship.
Oh well, I'm sure they'll implement gravity at some point, but for now, it seems, 3.0 will have wonky atmospheric flight.
In atmosphere, ships will expend maneuvering fuel in order to stay aloft. In order to refuel, they must go back into space, land and refuel, or get fuel from a starfarer.
In space, hydrogen is only expended at a rate greater than you can capture it when you are using afterburners or boost to maneuver more abruptly.
There is one major issue they need to fix, and that is collisions between ships and planets. Right now, ships bump into planets at full throttle and nothing happens. This is expected to change.