Quite simply you cannot. It is widely stated you would need to be at a height of at least 40,000 ft to get even a hint of curvature if earth were round. Commercial aircraft are not allowed to fly this high. They are only allowed to fly just under this altitude. 36,000ft might be typical. In addition, the windows on commercial aircraft are small and heavily curved. Even if they flew high enough for a person to see curvature, it would still not be visible to passengers.
173) NASA has several alleged photographs of the ball-Earth which show several exact duplicate cloud patterns! The likelihood of having two or three clouds of the exact same shape in the same picture is as likely as finding two or three people with exactly the same fingerprints. In fact it is solid proof that the clouds were copied and pasted in a computer program and that such pictures showing a ball-shaped Earth are fakes.
79.) The remark is common enough that we can see the circle of the Earth if we cross the ocean, and that this proves it to be round. Now, if we tie a donkey to a stake on a level common, and he eats the grass all around him, it is only a circular disc that he has to do with, not a spherical mass. Since, then, circular discs may be seen anywhere – as well from a balloon in the air as from the deck of a ship, or from the standpoint of the donkey, it is a proof that the surface of the Earth is a plane surface, and, therefore, a proof that the Earth is not a globe.
The placement of the sun and moon in the globe model vs. the flat earth model are vastly different from each other. In the modern heliocentric model we are taught that the sun is the center of the solar system, and that it is 109 times the size of earth and 93 million miles away. We are also told it is one of millions of stars in the universe and has its own planetary system. This is proven science, right? If the Bible doesn’t match “proven science” than we assume the Bible is just allegorical and make believe. But, what if it is the opposite? What if the Bible doesn’t match modern “science” because “modern science” is a lie?
152) In 2003, three University Geography professors collaborated in an experiment to prove that the state of Kansas is indeed actually flatter than a pancake! Using topigraphical geodetic surveys covering over 80,000 square miles it was determined that Kansas has a flatness ratio of 0.9997 over the entire state while the average pancake, precisely measured using a confocal laser microscope comes in at 0.957, making Kansas thereby literally flatter than a pancake.
25.) The surveyor's plans in relation to the laying of the first Atlantic Telegraph cable, show that in 1665 miles – from Valentia, Ireland, to St . John's, Newfoundland – the surface of the Atlantic Ocean is a LEVEL surface – not the astronomers' "level," either! The authoritative drawings, published at the time, are a standing evidence of the fact, and form a practical proof that Earth is not a globe.
41) Similar calculations made from the Cape of Good Hope, South Africa to Melbourne, Australia at an average latitude of 35.5 degrees South, have given an approximate figure of over 25,000 miles, which is again equal to or greater than the Earth’s supposed greatest circumference at the equator. Calculations from Sydney, Australia to Wellington, New Zealand at an average of 37.5 degrees South have given an approximate circumference of 25,500 miles, greater still! According to the ball-Earth theory, the circumference of the Earth at 37.5 degrees Southern latitude should be only 19,757 statute miles, almost six thousand miles less than such practical measurements.
It is certain that the theory of the Earth's rotundity and that of its mobility must stand or fall together. A proof, then, of its immobility is virtually a proof of its non-rotundity. Now, that the Earth does not move, either on an axis, or in an orbit round the Sun or anything else, is easily proven. If the Earth went through space at the rate of eleven-hundred miles in a minute of time, as astronomers teach us, in a particular direction, there would unquestionably be a, difference in the result of firing off a projectile in that direction and in a direction the opposite of that one. But as, in fact, there is not the slightest difference in any such case, it is clear that any alleged motion of the Earth is disproved, and that, therefore, we have a proof that the Earth is not a globe.

14 And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years: 15 And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so. 16 And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. 17 And God set them IN THE FIRMAMENT of the heaven to give light upon the earth, 18 And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good.

In 1956, Samuel Shenton created a more modern version of the Flat Earth Society, to collect a variety of followers of Rowbowtham's experiments. When the first images of the earth taken from space were released, Shenton claimed that they were false. In the 1970s and 1980s, they released a newsletter called the Flat Earth News, which often debated NASA and other space agencies.

112) The Sun brings noon to every time-zone as it passes directly over-head every 15 degree demarcation point, 24 times per day in its circular path over and around the Earth. If time-zones were instead caused by the uniform spinning of the ball-Earth around the Sun, every 6 months as Earth found itself on the opposite side of the Sun, clocks all over Earth would have to flip 12 hours, day would be night and night would be day.
108) The mariner’s compass is an impossible and non-sensical instrument for use on a ball-Earth. It simultaneously points North and South over a flat surface, yet claims to be pin-pointing two constantly moving geomagnetic poles at opposite ends of a spinning sphere originating from a hypothetical molten metal core. If compass needles were actually drawn to the North pole of a globe, the opposing “South” needle would actually be pointing up and off into outer-space.
88.) If we could – after our minds had once been opened to the light of Truth – conceive of a globular body on the surface of which human beings could exist, the power – no matter by what name it be called – that would hold them on would, then, necessarily, have to be so constraining and cogent that they could not live; the waters of the oceans would have to be as a solid mass, for motion would be impossible. But we not only exist, but live and move; and the water of the ocean skips and dances like a thing of life and beauty! This is a proof that the Earth is not a globe.
Both Davies and Hodgson talked of a reunion a couple of times, however, this would never come to pass. The first hint of a reunion came in 1993 when Davies and Hodgson reunited for an A & M dinner honoring Jerry Moss, co-founder of A & M Records. This dinner resulted in writing and demoing new songs, but it never went anywhere due to disagreements over management. Another hint of a reunion came in 2010 when Roger Hodgson approached Rick Davies about a fortieth anniversary of their very first album Supertramp (rogerhodgson.com). Rick Davies declined the invitation and any chance of Supertramp reuniting was squashed.
55.) The Newtonian theory of astronomy requires that the Moon "borrow" her light from the Sun. Now, since the Sun's rays are hot and the Moon's light sends with it no heat at all, it follows that the Sun and Moon are "two great lights," as we somewhere read; that the Newtonian theory is a mistake; and that, therefore, we have a proof that the Earth is not a globe.

9 And God said, Let the waters under the heaven be gathered together unto one place, and let the dry land appear: and it was so. 10 And God called the dry land Earth; and the gathering together of the waters called he Seas: and God saw that it was good. 11 And God said, Let the earth bring forth grass, the herb yielding seed, and the fruit tree yielding fruit after his kind, whose seed is in itself, upon the earth: and it was so. 12 And the earth brought forth grass, and herb yielding seed after his kind, and the tree yielding fruit, whose seed was in itself, after his kind: and God saw that it was good. 13 And the evening and the morning were the third day.
When the Sun crosses the equator, in March, and begins to circle round the heavens in north latitude, the inhabitants of high northern latitudes see him slimming round their horizon and forming the break of their long day, in a horizontal course, not disappearing again for six months, as he rises higher and higher in the heavens whilst he makes his twenty-four hour circle until June, when he begins to descend and goes on until he disappears beyond the horizon in September. Thus, in the northern regions, they have that which the traveler calls the "midnight Sun," as he sees that luminary at a time when, in his more southern latitude, it is always midnight. If, for one-half the year, we may see for ourselves the Sun making horizontal circles round the heavens, it is presumptive evidence that, for the other half-year, he is doing the same, although beyond the boundary of our vision. This, being a proof that Earth is a plane, is, therefore, a proof that the Earth is not a globe.
115) The existing laws of density and buoyancy perfectly explained the physics of falling objects long before knighted Freemason “Sir” Isaac Newton bestowed his theory of “gravity” upon the world. It is a fact that objects placed in denser mediums rise up while objects placed in less dense mediums sink down. To fit with the heliocentric model which has no up or down, Newton instead claimed objects are attracted to large masses and fall towards the center. Not a single experiment in history, however, has shown an object massive enough to, by virtue of its mass alone, cause other smaller masses to be attracted to it as Newton claims “gravity” does with Earth, the Sun, Moon, Stars and Planets.
26.) If the Earth were a globe, it would, if we take Valentia to be the place of departure, curvate downwards, in the 1665 miles across the Atlantic to Newfoundland, according to the astronomers' own tables, more than three hundred miles; but, as the surface of the Atlantic does not do so – the fact of its levelness having been clearly demonstrated by Telegraph Cable surveyors, – it follows that we have a grand proof that Earth is not a globe.
The Flat Earth, God’s true creation, is a beautiful, peaceful Truth, making you very valuable and the center of God’s Creation. The first chapter of Genesis clearly describes a flat, Stationary earth, set on pillars on the deep waters, with a glass dome (Firmament) above, and with the sun and moon inside the dome. The Ball Earth is a Satanic lie. It doesn’t exist, except on screens, in textbooks, and in people’s programmed minds.
This balloon footage from a high altitude piggy cam at 121,000 feet shows a flat earth! The flat earth horizon rises to eye level and has no curvature at all. Any slight "curvature" you see is from the lens and the movement of the camera. This is conclusive flat earth proof. When the camera is not moving, you can clearly see that the earth is also not moving. And you can see that the close, small sun is illuminating locally. If you have eyes to see, then see the truth! We are not living on a spinning ball!
A flat planet (ours or any other planet) would be such an incredible observation that it would pretty much go against everything we know about how planets form and behave. It would not only change everything we know about planet formation, but also about star formation (our sun would have to behave quite differently to accommodate the flat-earth theory) and what we know of speeds and movements in space (like planets' orbits and the effects of gravity). In short, we don’t just suspect that our planet is spherical. We know it.
Inferior mirages are the most commonly noticed type of mirage; therefore, in the minds of most people, it is the only type of mirage. An inferior mirage occurs when there is a layer of warm air in contact with the ground, with layers of much cooler air just above. This condition exists nearly every sunny day. As the sun’s radiation is absorbed by the ground, the air in contact with the ground heats. Air a short distance above the ground remains cooler, so a large temperature difference can exist between these two layers. Because this temperature difference is most pronounced when the sun is as high in the sky as possible, this condition is most likely to occur in the early afternoon in late spring and into summer. The type of surface exposed to sunlight is very important too, because dark, flat surfaces, such as pavement, rock, and sand are most efficient at heating air this way. Surfaces with much vegetation, such as grass, are far less efficient in doing this. Because of its high specific heat and great optical depth, water generally is very poor at producing conditions conducive to an inferior mirage. The above example of a 10-degree difference in air temperature is rather modest—much greater temperature differences occur under ideal conditions of early summer, decreasing the critical angle, and increasing the angle above grazing where an inferior mirage can happen.