When you live on a globe earth the observed horizon will always be flat unless you are very high up in an airplane. Commercial passenger aircraft just don't get to a sufficient altitude to make a meaningful observation of any curvature.
Incorrect. I was mistaught this as well. The horizon does not curve at any altitude attainable (including high altitude balloon). This does not have necessary bearing on the shape of the world; it's simply a demonstrable and reasonably repeatable/observable fact.
One of the reasons we were taught that tripe was to bolster belief (not knowledge) in the globe model. Often the bs (which is not to say certainly "lies") came directly from nasa which consistently continued to claim, decade after decade for approaching 3/4 of a century now, "it's just a little bit further than you can get to, but trust us - it's totally there".
Part of the misconception/misunderstanding is somewhat innocent, as lens distortion causes the effect that makes the horizon appear to curve (when it clearly, and logically, doesn't).
KNOWING something is great but that doesn't mean that it is correct.
Agreed. Generally/historically speaking, humanity is always wrong about everything.
In that case it would be much better to BELIEVE in something that's actually correct!
Belief is for fools, wisdom (generalized knowledge) for the wise. The chances of our vain self-serving belief being correct are consistently infentessimal, and we know this from validating/verifying/testing them over millenia. The scientific method is carefully crafted to avoid the natural and default self-delusion that belief constitutes.
If you take a ship out to sea with access to a couple of very high quality gyroscopes and inspect them day after day as part of your job and actually measure the curvature of the sea, and the earth the water is lying on, would that process result in KNOWING or BELIEVING?
You would know that gyroscopes precess in a specific manner, your tendency (which you must resist to do objective study and learn / obtain knowledge) will be to believe that you have measured the water curving which is itself a conclusion contingent on much more assumption/bias/belief you swallowed long ago. (Like that you understand all the sources influencing the precession of the gyroscopes, for one)
Those measurements, and many others, from completely different gyros on different ships, consistently indicate that the surface of the sea is curved in the manner consistent with a globe earth. Wouldn't it be reasonable to say that I now KNOW that the earth is a sphere
I do not mean to be dismissive, but you don't have that data ("those measurements") - nor does anyone. If you did, and others independently repeated/confirmed your measurements then we could begin to talk about such things (which I personally would find fascinating!). Without the measurements - we have little to discuss except your interpretation of them should they happen to exist anywhere outside your heart and mind.