Well, Earth is an oblate spheroid, so it stands to reason there is more oblate spheroid beyond the "edge"... or depending on which axis you are traveling along, upper atmosphere, and then space, or deep-sea, earth crust, and then planetary core.
Professor Piccard And His Flat Earth Discovery
https://www.youtube.com/watch?v=cGHH6_K57zA
In 1931, Professor Auguste Piccard / Swiss Physicist, Inventor & Explorer took the first ever balloon flight high above the Earth to the stratosphere and discovered a flat plane with upturned edges. In his pressurized aluminum gondola he reached 51,775 feet; about 10 miles above the Earth. This is his story, a story which has been omitted from our education system.