Declassified government documents state that the earth is flat & non-rotating.

Lets start with what’s to gain from the deception that the earth is round? Convince me of that first and then we can have a chat.

In aerospace engineering, "assume a flat, non-rotational Earth" simplifies local-scale calculations. It's quick for initial designs and short flights. For high precision, like in satellite or long-distance trajectories, Earth's curvature and rotation are fully accounted for using complex models.

None of those documents actually state the earth is flat and non rotating, just that to simplify calculations it can be assumed so. You have been told this before.

How is it possible to watch the sunset twice with a drone if earth is flat? In sunset you raise the drone and after a certain height the sun is visible again. Has this been answered in flat earth society in any way? This isn't an ill meant question.

They don't and you know it. They simplify calculations by ignoring bits of reality like Earth being spherical, temperature being variable, flying devices being slightly flexible and their mass not being constant.

For flight simulators, that is.

Flat earthers- the government conspires to hide flat earth. Also flat earthers- look at these government documents that prove flat earth.

You suck at reading comprehension. The docs themselves clearly state the flat earth modeling is used to make the math for aerospace tests more simple. The spherical model complicates the equations