It's not a new idea however neither Andreessen nor Musk hold appropriate clearances to access the required data to decide this. They're bullshiting.
Full disclosure, I worked on feeder programs to the F-35 program. There were many people way back then saying the plane couldn't be built at the set price point. Our simulation models suggested the benefits of AI controlled aircraft in the 1980s.
FWIW
Marc Andreessen is hopping on the Musk bandwagon and slamming manned fighter jets, saying there won't be 'spam in the can' if pilots aren't in the plane https://www.aol.com/marc-andreessen-hopping-musk-bandwagon-043434751.html