I read about this Flat Earth International Conference (honest!), and I can't believe the idiotic stuff that was written in the article. I'm going to ignore the paranoid claims about conspiracy and stuff. I'm not here to deal with their psychotic problems. However, I can deal with the science, and in particular, when idiots try to use physics to justify their stupidity.
Many flat-Earthers believe in testing the theory.Darryle Marble said he conducted his own in-flight experiment using a leveler to test if the plane was flying parallel to a flat Earth.
"If it were a sphere then the surface of the Earth still would have been curving underneath the airplane while it's flying level," he reasoned. "It’s so simple it'll go right over your head," he said adding that people who have flown planes allegedly told him they "haven’t seen any curvature."
First of all, they don't believe astronauts who have gone into space when they said that the earth is a sphere, but yet, they want to use human observation from airplane rides! This is an example of pick-and-choose.
Secondly, a leveler? Seriously?
Assuming that the plane is moving at a constant speed and at a constant altitude, this means that the plane is moving parallel to the earth's surface all the time. That's the definition of constant altitude. If the plane were to fly "straight with respect to the spatial coordinates", then it would be increasing in altitude! If that were to happen, the leveler will indicate several things (i) the acceleration due to the plan having to increase its altitude and (ii) gravity will act not straight down anymore. Any of these will affect the leveler.
But really, does the fact that if one head east continuously and end up at the same position later while in the plane, means nothing to these people?
There are many evidence that the earth is a sphere, and many of these are plain obvious. The fact that different parts of the earth having opposite seasons at a given time of the year is one clear example. A flat earth will not result in different parts of the earth having different daylight hours and different seasons.
But there is another clear test here that have been too obvious: using a Faucault pendulum. How would these idiots explain not only the change in the plane of oscillation of the Faucault pendulum over a period of 24 hrs, but also the fact that (i) the change in the plane of oscillation is in the OPPOSITE direction for those having the opposite season (i.e. northern hemisphere versus southern hemisphere) and (ii) there is no change in the plane of oscillation at the equator.
Of course, to understand the significance of this observation, one actually must know the physics involved in a Faucault pendulum, and the conservation of angular momentum. But hey, maybe physics and all these conservation laws are also more conspiracies.
Again, to paraphrase Kathy Griffin: "These people are proud of their aggressive ignorance."