I refer you Sir to the lnik I posted previously outlining the scentific study into the area of Santa Clausial Existence Theory. Sonic booms aren't actually the problem;
"600,000 tons traveling at 650 miles per second creates enormous air resistance --- this would heat up the reindeer in the same fashion as a spacecraft re-entering the earth's atmosphere. The lead pair of reindeer would absorb 14.3 quintillion joules of energy per second each. In short, they would burst into flames almost instantaneously, exposing the reindeer behind them and creating deafening sonic booms in their wake.
The entire reindeer team would be vaporized within 4.26 thousandths of a second, or right about the time Santa reached the fifth house on his trip."