No known species of the genus reindeer can fly. BUT there are 300,000 species of living organisms that still have to be classified, and although these are mostly insects and bacteria, this does not necessarily exclude flying reindeer that only Santa Claus has ever seen.
There are 2 billion children (people under 18) in the world. BUT as Santa does not (seemingly) supply any Muslims, Hindus, Jews and Buddhists, his work is reduced to about 15% of the total – 378 million children (according to the People’s Counties Bureau). With an average number of children of 3.5 per household this amounts to 91.8 million homes. We assume that every house has at least one good child.
Santa Claus has a 31-hour Christmas day due to the different time zones when traveling east to west (which seems logical). This results in 822.6 visits per second. Thus, Santa Claus has 1/1000 second time for his work for every Christian household with good children: parking, jumping out of the sled, climbing down the chimney, filling the socks, distributing the other presents under the Christmas tree, destroying all the leftovers of the Christmas dinner, Climb up the chimney again and fly to the next house. Assuming that each of these 91.8 million stops is equally distributed all over the world (which, of course, as we know, is not true, but as a basis for calculation we accept this), we get a total distance of 120.8 million km, Not counting the interruptions for what each of us has to do at least once in 31 hours, plus food etc. That means Santa’s sleigh is flying at 1040 km per second, which is 3,000 times the speed of sound. By comparison, the fastest human-built vehicle on Earth, the Ulysses Space Probe, runs at ridiculous 43.8 km per second. An ordinary reindeer manages a maximum of 24 km per HOUR.
The load of the carriage leads to another interesting effect. Assuming that each child gets nothing more than a medium-sized Lego set (about 1 kg), then the sled has a weight of 378,000 tons loaded, not counting the Santa Claus, which is described in agreement as overweight. An ordinary reindeer can not pull more than 175 kg. Even assuming that a “flying reindeer” (see point 1) can pull the TENALTH normal weight, you do not need eight or maybe nine reindeer for the sled. You need 216,000 reindeer. This increases the weight – not even including the sled – to 410,400 tons. Again, for comparison: that’s more than four times the weight of Queen Elizabeth.
410,400 tons at a speed of 1040 km / s creates an enormous air resistance – this heats the reindeer, as well as a spaceship, which re-enters the earth’s atmosphere. The foremost pair of reindeer must thereby absorb 16.6 trillion joules of energy. Per second. Each. In other words, they will go up in flames almost instantly, the next pair of reindeer will be exposed to air resistance, and it will freeze. The entire team of reindeer is vaporized within 5 thousandths of a second. Meanwhile, Santa Claus is subjected to an acceleration of the magnitude of 17,500 times the gravitational acceleration. A 120 kg heavy Santa Claus (which, according to the description, must be ridiculous) would be nailed to the end of his sled with a force of 20, 6 million Newtons. We come to the conclusion: If the Santa Claus should have brought the gifts someday, he is dead today.