What is a defining characteristic of major airlines compared to national airlines?

A defining characteristic of major airlines is their greater annual revenue. Major airlines typically operate on a larger scale than national airlines, which allows them to serve a broader market and offer a greater volume of flights and services. This scale leads to increased revenue generation through ticket sales, cargo transport, loyalty programs, and ancillary services. Major airlines often have extensive domestic and international networks, connecting a larger number of destinations compared to national airlines. This expansive reach and operational complexity contribute to their ability to generate substantial revenue streams, making them financially larger entities in the aviation sector.

In contrast, the other options can be considered less defining for major airlines when compared to national airlines. While operational costs may vary, they don’t universally define major airlines. Employee counts can also differ significantly based on the specific airline's operational strategies and market needs. Regarding aircraft fleets, both major and national airlines strive to diversify to meet various consumer and operational demands; hence, having a less diversified fleet is not characteristic of major airlines.