The car is incredibly fast, but there's a lack of connection to your actual ground speed. (automobilemag.com)
On its debut flight in Switzerland in June 2014, the plane reached a maximum altitude of 5,500 feet (1,680 m) and flew at an average ground speed of 35 mph (55.6 km / h). (scientificamerican.com)
I'm not a pilot so I don't to what extent commercial pilots double - check airspeed readings with ground speed readings from GPS. (scientificamerican.com)