I found a bug report on a similar issue with an included youtube video here: RC 1.70.141503 : Jet sound pops in very late. I noticed the same problem during my own testing, where the Gryphon and Black Wasp would zip past at about 100 meters away and the distant sound would pop in about 12 seconds later, with no sound for when it was up close.

I have confirmed the problem and narrowed down the aircraft and circumstances where the problems occur. I encountered problems with the Black Wasp and Gryphon, Wipeout and UCAV Sentinel at speed settings faster than limited. I tested aircraft with the AI flying first at full speed and then at normal and finally limited speed (using group speed settings). All other aircraft besides those four sounded normal at all speeds, and all of the aircraft sounded normal at limited speed.

We do have sonic booms with Shikras at the moment, and the other Jets DLC aircraft are able to produce 'distant rumble' sonic booms, but the nearby booms for those aircraft seem to be glitched at the moment. Bohemia is working on that here: https://feedback.bistudio.com/T124855

The Hellcat does appear to at least have collision lights at present. I can confirm that the searchlight can only be activated by the copilot, though that doesn't seem like a bug necessarily. I can also confirm that the searchlight is now static, and does not follow where the copilot/gunner is aiming. This does seem like something to fix.

Confirmed. You can see the light from the helicopter if you're in front of it, but you can't see a cone of light coming out of it if you're behind the Hellcat.

For Hellcats, you can use "copilot action ["SearchlightOn", vehicle copilot];" and set the copilot's variable name as copilot.

Followup: As of the current version (1.76.143187) the Hellcat bug appears to have been resolved. I tested playing as both an infantryman and as an offroad gunner. When I set the Hellcat to maximum skill level, it did take a few seconds to get lined up on me, but it killed me quickly and efficiently on the first pass. Couldn't have done it better myself. If anyone is still having any issues with it, make sure to set AAF as hostile to whatever faction you're playing, give the Hellcat a "DESTROY" waypoint on yourself, crank the pilot and copilot's skill up to maximum, and then wait for death. It shouldn't take long.

This sounds more like you not knowing how to use the editor than a bug. Place an area, then double-click the little indicator at the center to bring up an edit menu. You should have a menu option to change the color. It works fine for me...

As of the current version (1.68.141112), the bug with the Hellcat is still there, though slightly improved. I tried standing on the runway of Tanoa Airport, facing down a hostile Hellcat in what should have been certain death. Pilot and copilot were both at 100% skill level. The pilot fired occasionally (a huge step up from not firing at all!), usually missing, but incidentally damaging me a few times (!). He made a dozen or so strafing runs on my position. I gave up waiting to be killed after 10 minutes. Despite the improvement, the Hellcat still poses almost no threat to infantry when piloted by AI. Would it be possible to increase the AI's accuracy when piloting the Hellcat, provided their skill level is adequate?

I verified that it also does not attack when using the 'move', 'search and destroy' and 'loiter' waypoints. My submission is here: https://feedback.bistudio.com/T119479

I tested the same issue for a different reason and can verify your results. I took the role of the target and tried to get attacked by a fully AI-controlled Blackfish with 100% skill rating for all crew members. They didn't fire at me even once, not that they did a good job of pointing at me either. My report is here: https://feedback.bistudio.com/T119479

Addendum: I'm not certain it matters, but I just verified that at least as of the current version (1.62) the PO-30 Orca does have the ability to lock-on to targets while the WY-55 Hellcat does not.