When the plane is first coming in for a landing, still bouncing on the rough ground, the propeller comes to a stop. Moments later, as the plane actually stops, the propeller is still turning at full speed, and then stops again.
After the governor's guard is punched out and the foursome are making a quick getaway, only the pilot is visible in the passenger cabin of the rather small plane. The other three, who look tightly packed moments before, are not visible at all.
After landing, and Lon Chaney and the pilot are thinking about leaving the rest of the group by stealing the plane, Look closely, the planes wheels are still chocked with rocks. They could not have taken off.