The reason why this is still top secret comes down to just one thing.

That's my hypothesis. Major technological advances often come down to a simple insight about the physical world:

• Rubbing certain materials together creates fire.
• Heating certain rocks creates metal.
• Spinning certain rocks (magnets) around metal induces an electric current.
• Slamming certain rocks (uranium) together creates a nuclear fission reaction.
• (Action) (object) (condition) induces a gravitational wave?

Maybe the ability to control gravity comes down to just a single, obvious-in-hindsight concept like this. That would sufficiently explain why there's such mind-bending militant secrecy around the topic.

The people responsible for maintaining military superiority of the US/Western armed forces cannot risk anyone outside of the circle of trust finding out - i.e., that getting to the next technological level merely requires counter-rotating magnets, or harmonizing frequencies around a zinc-magnesium cavity...etc.

I used to think there's no way that human beings have anti-gravity and/or field propulsion technology. But recent statements by Daniel Gockerell mean we now have 2 relatively recent witnesses to instantaneous acceleration by structured craft under military control at close range (the other being Michael Herrera, whose account AARO appeared to confirm).

I conclude with an anecdote:

A business man seeks a meeting with the CEO of a major toothpaste company. He tells the CEO that he has a way to increase the company's sales by 30% next year. "It will cost next to nothing to implement, the company will bear zero risk, and it can be implemented overnight."

When the CEO asks how he can achieve such a miraculous result, the business man replies: "If I tell you how, you won't need me anymore. I'll only tell you if you agree to give me 25% of your increased profit, which you'll surely generate with my method."

The CEO considers the offer and decides that even a 10% increase in profits would exceed all of the investors' expectations, so he has nothing to lose. After they sign the agreement, the business man tells the CEO: "Make the hole bigger."