Expressed in the simplest of terms, it should be some kind of force which would oppose gravitation, annul it and make possible the levitation of bodies.
For physicists, antigravitation is a nonsense, since no such mass exists which could repel another mass, prevent the spread of gravitation or, like Verne's Cavorite, isolate a body from its influence. According to understanding available to date, this cannot be achieved – either by way of anti-matter or by some field.
For SF writers antigravitation and levitation are very desirable, but also so fantastic that their achievement and use by man are regarded as impossible, that even authors of this field are not too keen to write about those things, and they rarely do so.
For various “inventors” antigravitation is, just as it is for constructors of a perpetuamobile, a possibility of achieving fame by constructing some kind of anti-gravitational flying craft.
In the my previous work: “How the velocity of light can be excedeed”, I have shown that light is not a special // separate (or positive) physical entity and that velocity of light, c, is not the property of light itself but is, in fact, a vacuum or space transference constant - the ability or property of vacuum // space to transfer electromagnetic impulses at precisely that and only at that speed.
Using the existing methods and accelerators I have also shown that it was not possible to accelerate the particles to a speed exceeding the velocity of light, c, in other words, that this is not possible, not due to the increase the particle mass, m, but because the acceleratory effect of force F, which affects the particle - and which is transferred exclusively at the velocity of light, c, - falls towards zero when at the velocity of the particle v that is close to the velocity of light c.
Superluminal particle accelerator, download white paper
This article summarizes one of the topics covered in my book Prilog razumijevanju i kritici teorije relativnosti (Contributions To the Understanding and Criticism Of the Theory of Relativity), presenting an analysis of various interpretations of relativistic phenomena and of attempts to conceive an experiment that would make it possible to achieve supra-light velocity.
All articles are available here as PDF documents.