I wasn't expecting the inertial movement to be non-damped, since in OT you are mostly moving through air and it feels kind of wrong not to be subjected to some drag. Unlike in SE where it feels more space-ish, also because the ground detail is limited so I feel like in space anyway.
Technically such a mode is possible, a kind of no-gravity no-drag mode. The pseudo-flight mode was meant more to resemble aircraft flight curves.
"UFO" mode in Outerra already is, as you say, a non-damped, no-drag, no-gravity propulsion system from ground level into space- the only difference being a constant key pressure to facilitate this action instead of a
single key press and release designating another key to halt the action. These kind of simple, yet effective key actions make using SE a veritable pleasure for realistic, slow, multilateral floating movements and touchdowns while exploring the surface canyons and mountains of distant planets.
Implemented this way in Outerra- with ground detail as it is would produce much more than a small rush to say the least...
I had experimented with SE some time back, but I had not gone into depth with it. I'm somewhat biased towards the ground level detail, so I was trying to get lower and lower but the blur effectively imposes a minimum altitude below which you neither feel the altitude nor the planet size right anymore (Infinity has this problem as well, there's a limit on terrain level because of floating-point imprecision and computation demands). It was also rather unstable for this kind of use. But since then I've seen some nice screenshots of planetary surfaces made by others, so I guess it's getting better. I like how it pushes the boundary from the above, enhancing on the concept of Celestia. The author (who I understand is primarily astronomer) is quite an effective coder too.
Of course, this is what separates Outerra into a unique slot all its own- such outstanding ground level detail, combined with the ability in a heartbeat to move quickly into space.
The idea of future anti-gravity propulsion systems, able to bend space and time, certainly no longer regarded as science fiction in light of large research grants for serious science in this direction.
Many forward thinkers now beginning to realize flight in its present form basically is a type of violence against natural law screaming for a more harmonious approach as a much wiser solution for a millennial revolution of new technology...
Outerra seems headed ultimately where SpaceEngine
is residing now with fantastic results showing for both concepts- (obviously a kindred pioneer spirit existing in both developments). Recently SE in its latest ver 0.96 along with other new features, developed a brilliant "Universe Map" for celestial navigation (a real mind blower) holding a firm grasp on science as an excellent teaching tool- moving a pawn forward from Celestia. Howbeit, as you mentioned- SE still lacking ground level terrain detail of course where Outerra has excelled...
Years of development costs and time could be shaved for both in consolidating such engines headed in the same direction bringing forth an interactive 3D universe, where the impossible is made possible. Blazing this kind of trail where no one has gone before spells a big winner for everyone involved - the only losers being those afraid of venturing into deeper waters...
(Detoured somewhat above but I thought a few points worth bringing up-)
Bottom line:
Similar key controls such as implemented in SE seem a natural progression to play an important part in the evolvement of Outerra's full engine potential- hopefully coming sooner rather than later...
Joseph