First Bruce Sato is seen driving Rhino's All-terrain Vehicle, but when seen from the back, Alex Sector is in the drivers seat.
There is a curious shot in which Alex appears to be riding on Matt's back after they leave Thunderhawk to explore the Nazca Plain. There is a slight drop to the ground visible in their motion, indicating that Alex was probably using Jackrabbit and carrying Matt to a certain location.
When Alex is leaning out of Thunderhawk and puts his hand on the window, his fingers are all drawn with an extra line on them, as if he was wearing gloves.
Miles Mayhem gives the command "Viper, on" while wearing his Python mask instead of Viper.