[philip142au]

It’s rubbish, whatever propulsion method you have you still need to push the air out of the way to move the thing forwards which takes the same energy using imaginary gravitational waves or a jet engine. No magic is going to make the air get out of the way any faster

[evilduck]

We're well within the realm of sci-fi speculation here, but if you have a gravity generation device that can be directed you could augment traditional aircraft to safely allow for high G maneuvers or sustained accelerations that would otherwise be harmful to the pilot or the airframe. That would have some tactical advantages even if it doesn't mean it helps us go faster.

[thysultan]

The appeal of gravitational propulsion is in replacing xyz propulsion fuel with electricity regardless of medium(vacuum or not).

[stevenalowe]

it's intended for use in space, phil.

[gus_massa]

The main idea is to make a ray of gravitons (or whatever equivalent in other possible extensions of general relativity). For theoretical reasons, the ratio of momentum to energy is fixed at 1/c, which is 3.3E-6 N/kW, that is very low compared to ion thrusters or chemical rockets.

Moreover it's the same value that you get with a photon rocket, i.e a laser or a flashlight in the back of your rocket https://en.wikipedia.org/wiki/Photon_rocket

So even in space, it is not very useful and you can replace it with a more simple and more efficient device.