Continuity mistake: When Decker first exits the aircraft, there is a jeep immediately behind it, a service truck behind the jeep, and a USAF F-100 Super Sabre jet in the background. However, when Maj Wilson escorts him away from the plane, the service truck is gone and the F-100 has been replaced with a large transport aircraft.
Continuity mistake: After Decker escapes from being held and heads back to his plane, he does not have his overcoat or scarf, and does not put them on when he starts his plane and climbs on board. When Major Wilson lets him go and he's taxiing away, in one shot he has the overcoat and scarf on, with no time to do so.
Continuity mistake: When the Ground Crewman runs after Lt. Decker, he reaches him just as Decker is climbing onto the plane. You see the Ground Crewman put his hand (or just about to) on Decker's upper left arm. When they cut to a closer shot, the Ground Crewman's hand is in the process of moving up to Decker's arm.
Continuity mistake: When Decker first gets out of his plane, Maj Wilson begins to question him. Decker's hair is neatly combed. When Wilson asks him "Are you French?" the shot changes to a closeup of Decker only. His hair is now disheveled in the front and hanging down on his forehead. The next shot returns to the wider angle and Decker's hair is more neatly combed again, as it originally was, not hanging on his forehead.
Continuity mistake: The jeep driver is standing behind Lt. Decker's aircraft during the initial conversation between Decker and Maj Wilson. His hands are behind the fuselage in the initial shot. When the shot changes to a close up of Decker, the driver's hands are now on top of the fuselage.
Answer: It's explained in the episode. The aliens are experimenting to see how humans react to various scenarios. This just happens to involve them using super strength.
Thanks. It's been a long time since I saw the episode so I forgot.