Distance basically drops to zero when you lose line of sight too. You can find references to Lora being used from a balloon with 40km distance and even from orb

Distance basically drops to zero when you lose line of sight too. You can find references to Lora being used from a balloon with 40km distance and even from orbit but you will never reach that even on a perfectly flat plain (the ground affects the signal unless each antenna is quite high off the ground).