What is the meaning of 'stall' in this sentence?
The sentence means the airplane was slowed down (generally) and the nose pulled up until the wing stopped generating lift (stalled) and finally "killed the engine" (typically by reducing the mixture until the engine stops running) and then landed by just gliding down to the airport.  Stalls are not a good thing when low to the ground and maneuvering for a landing, as there is no altitude left to recover, so we practice them to recognize when one is about to occur to avoid them, and to recover quickly at the onset of one.