Final answer:
If a commercial jet enters a brief period of free-fall like an air pocket, unbuckled passengers would experience weightlessness as they, and objects around them, float inside the cabin due to falling at the same rate as the cabin itself.
Step-by-step explanation:
If a commercial jet flying at 600 miles per hour were to enter an air pocket and experience 0.5 seconds of free-fall, the unbuckled passengers inside would also momentarily experience free-fall, which would result in a sensation of weightlessness. During this brief period, passengers and any loose objects within the aircraft would float inside the cabin as if there was no gravity acting upon them. This happens because both the passengers and the cabin are falling at the same rate of acceleration due to gravity, which is approximately 9.81 m/s2 (if we ignore air resistance). However, this scenario is highly theoretical, as modern aircraft are engineered to avoid such occurrences, and an 'air pocket' or region with significantly reduced air pressure would not cause a vacuum that leads to free-fall.
When a commercial jet flying at 600 [mi/h] hits an air pocket and goes into a 0.5 [s] free-fall, the unbuckled passengers inside will experience a sensation of weightlessness. During free-fall, the passengers and any unsecured objects inside the plane will float momentarily as the plane and everything inside it are in free-fall together. However, if the plane does not regain its balance quickly, the passengers may experience sudden forces as the plane exits the air pocket and returns to normal flight.