Getting around in space is very wasteful because the only known way to do so is to take some mass (matter) and throw it out the back of your ship as fast and hard as possible (thus "Newtonian motion": action producing reaction).
The reports of a device that claims to derive thrust without throwing matter away can be seen here on The Verge (The EM drive) I am not surprised if it doesn't work, since the idea behind it seems to be vague and it is hard enough to make a real object from a clear idea.
But . . . .
There are also a number of variants of a mechanical thrust-producing device loosely termed The Dean Drive.
Look here and here at Steve Hampton's site. This is very different from the previous example which featured microwaves bouncing around in a metal container: the site includes video of mechanical devices that can and do provide thrust without exhaust or movement of the outside medium (air or water).
Okay, I amit that I want to beleive this, but there is something more to it: on the Dean Drive page we see simple diagrams explaining how it works. If Steve Hampton has faked it, why did he keep building more versions and models if the first one didn't work?
I fully expect that this type of drive will not be able to get a ship into space or levitate a car against gravity - the thrust derived for weight of the device would make that very difficult, but it could be used to drive things in space provide it works as shown in the video . . . . so the question then becomes "Why is this not getting researched by NASA and others?"
Here are my probable answers, you can choose among them for yourself.
1. Science has become a bureaucracy and it has rules, the most fundamental being Newton's laws of motion. Anyone claiming to modify or otherwise alter these holy laws is automatically wrong.
2. Trendy scientist don't like mechanical devices any more - they are too "last century", and scientists have already discovered EVERYTHING about mechanical devices. If it were solid state and involved electronics, that would be okay.
3. Something to do with patents, lawsuits, ownership and so on: someone already has claimed this and will sue the ass off anyone trying to use it for serious commercial gain.
4. NASA has already tested it and it didn't work in space - so show us the proof - the Youtube vid where they tested it on rails (or whatever) in a vacuum chamber and it DIDN'T move.
DON'T give me any long winded "explanation" by a Ph.D about why "it won't work".
Ah, but I really don't expect any replies to this. Nobody reads this, it's just my own example of one hand clapping.