Okay, so here are my initial thoughts on the HUD.
First up, very cool, and could very easily put implemented as-is and be 100% functional. Most of my critiques are admitting subjective, dealing only with relatively minor issues. For that reason, this might come off as really nit-picky, but that’s only because the HUD as it stands right now is so good. 
1) Shield Indicators
I have two thoughts on this.
I’m slightly confused on the exact means by which the indicators indicate, but I am opposed to the fading in strength with decreasing shield values. I get that it will fade out when shields are full, but is the plan to let it fade in strength with falling shield integrity?
Regardless, I’m opposed to this method, as well as color shifts. The reason being, the indicators are relative, eg “How bright is that line?”, How orange is that line?", etc. Granted, with experience this will become a non-issue, however I’m not a fan. Becoming good at judging line brightness/colour is not necessarily a skill that should be crucial.
Again, I’m not sure how they are currently supposed to do it, but I suggest a ‘progress bar’ approach, eg lines shortening until empty, then a flashing red line.
A second issue I have with the shields is the location. You have six indicators for six shield sections all in four separate areas of the HUD. A quick check up on shields will require the eyes to move to four separate areas of the screen. I would suggest to centralize the info and perhaps place it next to/on top of the hull strength indicator.
I see two ways to centralize, each with it’s own philosophy.
One way would be to simply miniaturize the shield circle. It would be slightly more difficult to gauge, but it would be more useful for a quick glance check up. This would be used for smaller shields, with a quick recharge, so interceptors and bombers would benefit from this system.
Another method is to replace the circle with a percentage system. More time might be needed to process the info, as you would have to read. However, I see this being useful when shields are so big that attacks from smaller ships won’t really register a change on a circle, as it would be the difference of a pixel or less. But when in combat with larger ships, the ability to judge exactly how strong one’s shields are would be helpful. So this would be used on destroyers, carriers, etc.
In my opinion, the option should be their to switch to whatever indicator one would prefer, either on the fly or in the options menu.
In any case, the current shield indicators are somewhat camouflaged by the speed/hull indicators. I would make them more distinguishable.
2) Squadron list
This also spills a little outside of the squadron list.
First off, for a pure flight experience, this isn’t really needed on-screen, but given this is a combat game, this should be seen. It’s placement/size is good, so nothing there.
As to the content, the colour change is good, but the little bar to the far right is too small, and it’s function is unclear.
I would somehow emphasize the squadron number rather than the names.
When squadron members get on screen, I would remove the name entirely, and just have the squadron designation, for two reasons. First, I don’t really like reading fast moving text while trying to say something to that person. Reading a number allows for quicker communication. The difference is when trying to tell “7A, someone’s behind you” or “Bo0m3rL33T007MLG360noscopeXxX someone’s behind you”.
For these reasons, I would consider removing the names of the players from the squadron list (at least on the HUD). Again, a dedicated menu would be good for more detailed info, but on the fly not really needed.
If people want the names up, then a menu option should do the trick.
3) Weapon indicator
Assuming that the vertical progress bar is a heat mechanic or an indicator of how full the magazine is, it’s too small. I would turn the entire icon into a horizontal progress bar.
Assuming that the vertical progress bar is an ammo counter, then I would remove it, and stick with the numerical counter below.
I don’t see the need for two counters, a numerical and a visual. For something like ammo count I think the numerical counter would be more helpful.
4) Altimeter
In most of the flight games I’ve played, the altimeter is next to the pitch indicator. I see it as slightly being more helpful in the center.
Well, I’m out of ideas at the moment. Maybe you’ll find some of this useful, maybe not.
Anyways, again, looks great!