from Dick L. was interesting enough to re-post here.
As a pilot with a commercial license. single and multi-engine, and with an instrument rating and several thousand hours logged time, I owned a Cessna 172 and had a weekly flight from Augusta GA. to Andrews NC. — about a 120-mile flight. On one flight departing from Daniel field in Augusta GA. with a weather report of CAVU (“Ceiling And Visibility Unlimited”) that is Clear & no clouds on climb out from Daniel field at about 1200 feet looking ahead to the northeast, I continued my climb to the 6500 feet cruise level I had selected, and I realized the visibility was 100+ miles and what I was looking at were the mountains in North Carolina ahead of me. I continued the flight and when crossing Interstate 85 in South Carolina, I looked to my left I could see downtown Atlanta GA and to my right Charlotte NC, and was just about exactly halfway between the two, I could see clearly the buildings in each city from over 100 miles distance! (Charlotte to Atlanta via I-85 is 244 miles.) At 100 miles the supposed curve drop of 6650 feet would have made the buildings appear over a mile lower than I was and it should have looked to me that I was over 12000 feet instead of 6,500! There was no visible curve in either direction. Because I had been trained (brainwashed?) into believing that the earth is “too big” for me to observe the supposed curvature, I thought little of the incident at the time. Now that I know the formula for measurement (8″ X the miles squared), I can honestly state with great conviction that there is no observable curvature of the earth, period!