Superluminal communication is possible, as Hawkings suggested, provided that nature has it's own, so far undiscovered, way of protecting causality. Here is an excelent paper on super-luminal communication in the electro-magnetcic near field:
Near-field Analysis of Superluminally Propagating Electromagnetic and Gravitational Fields by William D. Walker
I don't see how near-field physics is useful in far-field scenarios like interstellar communication.
I've been thinking about the physics of interstellar spaceflight with a broader view over the last couple of days after reading some of nivek's old posts. Here's a brief overview of my line of reasoning.
The reports clearly indicate a gravitational field propulsion mechanism. Apparently a whole of lot of civilizations have figured out how to do it, because the performance characteristics fit the theoretical predictions
perfectly.
We know that this is only possible if a civilization can produce both positive (ordinary gravity) and negative (dark-energy-like gravity) spacetime curvatures.
This has massive implications, because the negative gravitational field is the key component required to produce effects that from our comparatively primitive scientific perspective, seem like magic.
Wormholes are in play when you can produce both positive and negative gravitational fields. Just like we've seen in the show Stargate SG-1 (but without the pretty watery effect), a pair of wormhole devices would permit instantaneous travel between two distant points in spacetime. But a wormhole is also an ideal instantaneous communications portal across arbitrarily large distances. In fact, it would only require a very tiny wormhole to relay communication signals instantaneously between two widely separated points in spacetime. The only limiting factor is the requirement of placing a wormhole portal at the point where you want the signal to arrive.. With a capability to create a gravitational field propulsion device - which these craft are clearly employing - wormholes are a modest step forward.
The primary objection against the existence of wormholes is that they could be used as a time travel device if one end of the wormhole is moved at relativistic speeds for awhile. I don't think that this is correct. Because if you accelerate the device that's holding one mouth of the wormhole open, the device itself will age more slowly with respect to the unaccelerated device at the other end of the wormhole - but
the spacetime itself will not age more slowly. Spacetime isn't "stuff," so it's not subject to Lorentzian time dilation, like matter is. So I think that argument is just plain wrong: you can't use a wormhole to make a time travel device.
With control over both polarities of gravitational field, you could also produce bizarre spacetime geometry effects, like a craft that's larger on the inside than the outside. So these craft that appear to be 30-50ft in diameter, might be several times that size on the inside. It sounds absurd to us, but the capability to engineer spacetime in a manner required to produce gravitational field propulsion also presents that possibility.
It's probably also possible to open a spacetime tunnel between two points using a properly engineered gravitational beam, and pull something through that tunnel, even if there's a wall in-between. It might be tricky to pull that off without altering the structural integrity of the matter in the way, but I'm not convinced that it would be impossible.
Another clear possibility is time control - increasing and slowing the rate of time between two reference points. So in theory an alien craft could show up over your house, and either pull your body, or perhaps just your consciousness somehow, through a kind of wormhole tunnel, and spend a few hours of interior subjective time running experiments, and then return you to your bed just a few moments after you left.
Extrapolating the possibilities from what we've seen to be true, the propulsion system alone, opens up a raft of physical possibilities with regard to long-range communication as well as interstellar travel, and somewhat to my surprise, lends new credibility to the abduction phenomenon.