As we approach Gander, the tail winds are up to 169 mph, pushing us along at 50 mph faster than the speed of sound,
No it's not. The speed of sound is variable. At a temperature of 15 degrees Celsius and at sea level, the speed of sound is 761.2mph. At 36,000ft for example it could be as low as 654.6mph. Irrespective of that though, your speed is only relative to the air surrounding the aircraft, and you will have been cruising at about Mach 0.81, which is 81% of the speed of sound.