Which of the following was NOT a change in aviation security from 1980 to 1990?

The correct choice is the global ban on all air travel, as it did not occur during the period between 1980 and 1990. While the decade did witness significant advancements in aviation security in response to various threats, a complete ban on air travel was never implemented during this time. Instead, safety measures such as the screening of checked baggage, the introduction of behavioral profiling techniques, and increased emphasis on positive identification and monitoring of personnel all became standard practices in the aviation industry as a result of rising concerns regarding air travel safety and security.

The other options reflect real changes that occurred during this period aimed at enhancing security protocols and addressing the growing threats to aviation. The introduction of these security measures was a proactive approach taken by airlines and governments to maintain passenger safety and restore confidence in air travel.