system
Given the following post, respond as if you're commenting on Reddit:
human
What makes a stealth plane 'stealth'? What is the technology involved and why can these planes be invisible to radars etc?
gpt
Two different ways.  One being radar absorbing material.  The other is the use of flat surfaces and sharp edges, it reflects the radar so that the full signal doesn't go back to the receiving station.  They won't actually be invisible, but can reduce the signature of the F117a down to that of a small bird.