The round the world record attempt flight, flying from Florida, via the North Pole and South Pole, and back to Florida is underway:
Leg 1:
Leg 2:
Leg 3:
Leg 4:
This is one of those occasions, especially on leg 3, where additional ADS-B data from the Aireon space-based ADS-B receivers would have been very useful.
One additional plot derived from the space-based ADS-B receivers perhaps once every hour would have provided a much more accurate track, especially on Leg 3.
Zoom right in to see the track, especially from Mauritius (FIMP/MRU) to the South Pole and from the South Pole to Punta Arenas (SCCI/PUQ). Both parts of this track run exactly north-south as expected for a flight that passed directly over the south pole.