Evil mathematicians mislead us against nature: 'on a flat surface the far ends would be seen!'
With an optical help (i.e. telescope) the lower portion can be seen
It is really very simple to build a circular level for measuring the amount of inclination of a plane while flying from a country to another: around a protractor clue a transparent hose which is filled with alcohol or any other light liquid, a small bubble is enclosed within the hose.
This circular level can be put in any visible place. If the plane follows a circular path, the marks of inclination changes around 1º each 110 km. If the plane follows a straight line, the bubble would keep almost at the same mark.
Paraborne.com: As stated, an observer on the ground would see the air going almost straight down behind the plane. This can be demonstrated by observing the tight column of air behind a propeller, a household fan, or under the rotors of a helicopter; all of which are rotating wings. If the air were coming off the blades at an angle the air would produce a cone rather than a tight column. If a plane were to fly over a very large scale, the scale would register the weight of the plane.
NASA: Depends on one's frame of reference! In the frame of the air or the ground, the airplane is indeed in motion. But one could also calculate everything in the frame of the airplane, where it is the air that is moving. As long as the airplane flies in a straight line with constant velocity, the same laws apply.
BobTilden.com: When I am being proper and responsible, I am flying high, maybe even 3000 feet above the ground. From that height, on good days I can see almost forever around me, but the details of the ground below have started to blend together and flatten. The view becomes more oriented to the sky than the ground as I fly a straight line to my destination.
guidetopsychology.com: Commercial aircraft prefer to fly “straight and level” because it is convenient. Air traffic controllers have to keep aircraft from flying into each other, and having pilots fly airplanes in straight lines makes a controller’s job possible. Also, people tend to get airsick when an airplane moves erratically, so straight and level flight makes things more comfortable for the passengers and crew.
On August 2002 I took a plane from Maiquetía Airport 10º36' north to Lima -Peru at parallel 12º03' South, that is 22º39'. I took a circular level with me, placed in the direction of the flight. At the ground the bubble was above the 90º mark. When the plane took off the mark moved to the 45º, and it returned to the 90º mark when the plane reached its height of flight, and it kept there for all the trip, until it inclined to go down:
The flight that we took was from JFK International Airport to Los Angeles International Airport (LAX), LAX to Fiji, and Fiji to Melbourne. The flight from JFK to LAX is 5 hours, from LAX to Fiji is the longest flight at 11 hours, and the flight from Fiji to Melbourne is another 5 hours. Therefore, the total flight time was around 21 hours not including layover time in Los Angeles and Fiji.
United Airlines' Flight 821 was to leave New York's John F Kennedy airport at 10:50 am (1450 GMT) yesterday, and arrive in Hong Kong at 2:30 pm (0630 GMT) today in a flight lasting 15 hours 40 minutes and covering 13,580 kilometres, the spokesman said.
Quotes Direct from the Brain Trust Videos 2001 Aug 11: "Gravity as Newton and Einstein knew it does not exist. You have to go back at least 15 years when they put gravitometers down oil wells about six miles deep to test the gravitational constant at that level. According to Newton and Einstein, it should be a certain specific quantity or within a small range. In fact, they found out that there is something like a hundred times as much gravity and that's ridiculous, they said. When the United States launched the first space probe it kept going off course. Well, it took them awhile to re-analyze all the evidence and what they came up with is that gravity does not exist in space as they thought it did -- there's less than 1percent of the amount of gravity that there should be. So gravity as Newton and Einstein knew it works from about five miles under the earth up to about three-hundred miles above the earth. Thus, gravity is not what anyone ever thought it to be."