our existing spy planes and drones are subsonic and work just fine loitering over poorly-defended targets.
stealthy or speedy aircraft could work over more hostile places and add to the satellite capabilities. Maybe there are things you can sense from 10 miles up that you can't at 100mi. And maybe there's some brand new gear that you don't have in space yet. And maybe you want to time your picture with some unpredictable events on short notice. there are a ton of reasons to have this variety of capabilities.
stealthy or speedy aircraft could work over more hostile places and add to the satellite capabilities. Maybe there are things you can sense from 10 miles up that you can't at 100mi. And maybe there's some brand new gear that you don't have in space yet. And maybe you want to time your picture with some unpredictable events on short notice. there are a ton of reasons to have this variety of capabilities.