Yes you will weigh less if you go very high, especially on the right day with the right conditions.
If you go under water you will [appear] to have more weight the farther down you go. This is simply because you have more weight above you weighing you down.
With the billions of particles in the air: vapor, oxygen, other gasses, dust particles, etcetera, as well as the clouds weighing thousands of tons, all of these things weigh down upon us (remember to a scientists there's no difference between liquid and gas). Just like in the water, the higher we go the less there is weighing down on us. We appear to weigh less. But in reality our weight hasn't changed, it's the particle density. And particle density is also reliant upon atmospheric conditions - humidity and heat. Talk to any seasoned pilot and he will tell you about particle density.
Because gas and air is the same, we are in water - though it is much less dense water. This is the Aether. When the Bible says that there is a separation between the waters and the waters above, it's possible that it's speaking about the different densities between water and gasses—ans we move within the upper waters. The more accepted theory, which may be true, is that the waters above is speaking about the waters above the firmament, which came down during the deluge. Either or both could be true. It's quite apparent that according to the Bible there is literal H2O water above, because otherwise how would it add to the amount of H2O that physically covered the earth? One day we will know.
—