If gravitational waves can scatter or reflect. That will make it possible to create real antigravitation.

The antigravitation could be a simple thing. Above the object is formed the gravitational field or gravitational wave that pulls the object up. Or in some other version scattering of the gravitational fields or gravitational waves causes the gravitational field around the object turns weaker. 

The problem is that nobody ever scatters or reflects gravitational waves. But those things are in a key role in hypothetical antigravitational systems. 

The problematic thing is that the scattering or reflection of gravitational waves should be possible. But nobody knows how to make those things in real life.

One version of those systems is the gravitational maser that pushes other gravitational waves away from the object. Turning wave motion by using counterwaves is possible in other frequencies. And that means also the gravitational waves can turn away by using counter gravitational waves. 

Those counterwaves can create a more powerful gravitational field over the object when they increase the power of other gravitational waves. And those gravitational waves can pull the object up from the ground. 

Or is gravitational stealth possible? 

Or there is a possibility that there is the form that makes gravitational waves slide over that form like radio waves are doing in stealth planes. So the question is could there be some kind of form that makes a similar effect to gravitational waves that stealth-shape makes to radio waves. 

The thing is that it should be possible. Because the radiowaves are sliding over the stealth shape. There should be possible to make a similar shape that makes the gravitational waves slide over the structure.

Gravitational waves are wave motion. And they should act like all other wave motion frequencies. When the gravitational wave hits with counterwave it should lose something from its energy. The counterwaves can raise the height of the waves. 

So the gravitational counterwaves can rise the gravitational waves above the object higher. And that forms the stronger gravitational wave above the object that pulls it up. 

Wave motion can turn around by using counter waves. And the similar thing can be done with gravitational waves because gravitational waves are wave motion. 

The major problem is this. This system requires the ability to create synthetic gravitational waves and control them. But the antigravitation could be an awesome tool for many things. It could remove air molecules from some areas. Or that system can move objects without electromagnetic fields.