Which of the following aircraft does NOT fall under the category of Executive Mission Aviator?

The U-28 does not fall under the category of Executive Mission Aviator because it is primarily a military aircraft used for intelligence, surveillance, and reconnaissance (ISR) missions. Its focus is on operational capabilities for combat and tactical scenarios rather than executive transport.

In contrast, the other aircraft listed serve specific roles in transporting high-level government and military officials, which aligns with the definition of Executive Mission Aviators. The C-40B, C-32A, and C-37A/G-5 are designed with the necessary amenities and configurations to support missions that involve government executives and other dignitaries, ensuring their comfort and security while traveling. Therefore, the U-28's function as a tactical ISR platform sets it apart from this category.