system
Given the following post, respond as if you're commenting on Reddit:
human
Why do some aircraft, such as the F/A-18, feature canted tail fins, despite also having "flat" horizontal stabilisers?

The F/A-18 Hornet, among other aircraft features canted fins, as well as traditional "flat" horizontal stabilisers. Why is this?
Why do the fins need to be canted? Why not just have them pointing straight up, at right angles to the stabilisers, or just have a traditional v type tail? There must be a reason but I can't put my finger on it. Anyone?
gpt
I can't speak for any aerodynamic reasons, but right-angles such as between traditional vertical/horizontal stabilizers have a very high radar cross-section. Essentially it acts somewhat like a corner-cube and reflects a large amount of radio waves back to the transmitter. Military aircraft tend to like lower cross-section aircraft for obvious reasons. You'll notice that true stealth aircraft, namely the F-22 and the F-117 also implement this feature as one of many strategies to mitigate their radar cross-section.