Some interesting discussion that can really take you down a wormhole, pardon the pun. This Bob Lazar guy is an interesting fella. Seems like what he says stacks up to what we've discovered about the universe, some of it recently.
What is interesting is he speaks to the exact technology and how it works. He also talks about an element (115) that was non-existent but the fuel to drive the vehicle.
Stephen Hawking doesn't rule out the possibility of travel like this, or even time travel. Like I said, a really interesting topic that has consumed way too much time.