Something ends, something begins. We are at a time in history which the textbooks describe with maps with arrows on them.
It's almost like heavier than air vehicles were never invented.
There might be a market for fast, lightweight, extremely cheap aircrafts. No border wall defenses will help if you swarm them with more planes than they have anti-aircraft missiles.
It it is fast and lightweight and cheap shooting it down also won't be hard. you don't need a missile, you need a bullet.