Planes without atmosphere?

Ah, space stuff, how ye doesn't work.

I think trying to convert momentum from direction A to B is probably my failure here. I was sort of under the assumption that the aircraft in PA should have engines able to aim in basically any direction (or can make up for it with the use of multiple) in order to create that stopping power called friction we have down here where laws of physics are a bit more understandable.. At least using engines able put forth thrust in any direction, you should be able to do what I thought, but I guess without small engines that are powerful enough, you'd need so many that the ship would look kind of ridiculous.

I also didn't know the boosters they use to correct their trajectory are simply the things on this page and not really capable of moving the ship much otherwise. I knew what they did, but I guess they're not powerful enough to do much else.

But that's why the units in PA are The Best™. They do things we don't even consider possible, right?

..right?

I honestly like the idea of having a planet type that doesn't allow winged aircraft. However, I don't mind the possibility of some sort of gunship type thruster-based craft that can operate on moons/asteroids, but only if ground units are able to target these types of vehicles. Plus, if realism was the reasoning behind this,you would have to rule out hovercraft (unless it was like anti-grav rather than a pressure skirt).

+1 in terms of gameplay. There are planets that can limit everything other than air units. This should be that thing.

Actually, hovercraft do exist, (the 'flying cars' you can see here), they simply use multiples of large fans as propulsion just like helicopters do. The military has working hovercraft, and civilians are simply behind since we don't get their technology till it's already out-of-date. Eventually we'll use jet thrusters as well (IE: the Harrier). It's even possible to use water for thrust. (Mythbusters did it with a car shell, you just need a lot more oomph to lift the same shell with an engine and etc.)

Harrier jets use the same type of hovercraft style thrust to take off vertically, they just use enough to get airborne, not hover over the ground. It's a solid concept, but the technology isn't thrown widespread so the general public can use it. There's a reason one of the only VToL aircraft using jet thrusters is part of the military, and also one of the reasons the public has to use helicopter-style lift to make VToL vehicals.

PA is in the far future, where technology is so advanced, they have teleportation, engines so large they can move planets, and cannons so big they can fire units the size of a city block through space at an entire different planet body. I don't think hovercraft will be a problem.

Agree with this. Gas giants will be aircraft only, so why not have non-atmospheric planets nullify winged aircraft, and only support thrust-controlled aircraft like gunships.

Actually the gravity the majority of sattelites experience is still around 90% of surface gravity. The sattelites that don't are the Geostationary ones (they are further away than the moon's orbit!), and the GPS sattelites (Closer to the moon's orbit than earths surface)

Also, wouldn't it need more thrust to stop momentum if it couldn't use earth's gravity to do it (assuming moving away from earth)? Unless you want to stop it from falling towards earth of course, but that wasn't the issue in this case.
If you mean stop momentum in orbit, then the gravity doesn't really matter. What matters is the mass and velocity of the object you are trying to stop.

Yes, I am aware of different types of methods that produce lift Pressure skirts are the most efficient method of hovering, but all methods you mentioned still require an atmosphere and would thus fall under the same category. Turbo-fans require air just as much as helicopters do.

Regardless, this should be done. I don't like using air, so I want at least one planet type that doesn't support it!