After reading through a few answers about long distance/international traveling in the HP universe, it seems that apparating over very long distances is not advised/practical/etc due to the extreme unreliability which led me to this question. Why couldn't a wizard apparate a shorter, safe distance (say <50 miles?), then immediately apparate to the next intermediate stop, and so on. For example, notwithstanding the illegality/banning of apparating into another country, couldn't an enterprising wizard apparate over the English Channel to France, then skip his way across Europe to Asia, etc?
Or to take it a step further, why couldn't a wizard theoretically (although probably ill-advised) apparate across the ocean by going whatever the safe apparate distance is and "landing", say 100 feet above the water, then apparating again the next leg before hitting the water, and so on. It makes me wonder if Voldemort's flying spell might be some sort of version of this, akin to a computer script of a bunch of repeating micro-apparates.