Which fighter aircraft is primarily associated with the Block 4 upgrades?

The F-35 Lightning II is primarily associated with the Block 4 upgrades due to the significant advancements and enhancements being implemented to improve its capabilities. Block 4 focuses on integrating new technologies and operational capabilities that enhance the aircraft's ability to conduct missions across the modern battlefield environment. This includes improved sensor fusion, advanced electronic warfare capabilities, and enhanced communication systems that facilitate greater interoperability with allied forces.

The Block 4 upgrades are specifically designed to allow the F-35 to remain competitive in future conflicts by integrating next-generation weapons and upgrades that are necessary for countering emerging threats. This commitment to continual improvement ensures that the F-35 meets the evolving demands of air combat.

While the other aircraft listed have their own upgrade programs, they are not centered around the Block 4 designation, which distinctly pertains to the F-35 program. The F-22 Raptor, F-15 Eagle, and F-16 Fighting Falcon have separate modernization paths and do not have the same integrated approach as the F-35 concerning Block 4 enhancements.