Comment:  As threats heat up, this blimp solution is being revisited.  
 Joint Land Attack Cruise Missile Defense Elevated Netted Sensor (JLENS) 

Quote from Air and Space Forces 24 July 24:

Inside Defense   [Requires a Subscription]

Congress, which in a fit of emotion nearly a decade ago terminated the U.S. military's main dirigible project that looked deep over the horizon to detect cruise missiles, is once again interested in the potential of airships and aerostats to help defend against not only cruise missiles but also ballistic and hypersonic threats as well as drones.

https://insidedefense.com/daily-news/decade-after-canceling-jlens-lawmakers-now-interested-dirigibles-air-defense

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https://www.defenseindustrydaily.com/jlens-coordinating-cruise-missile-defense-and-more-02921/

The JLENS System: This is Not Your Grandpa’s Barrage Balloon

Air Defense Artillery Magazine, Major Thomas J. Atkins