We’re planning to release a gameplay video right after the KS campaign has launched. I’ll demo the prototype with commentary, and will go into more details as to what all these little things do.
You’ve already figured out the left bars, the right bar is the speed meter ( altitude is displayed as text on top of it ). The white arrow is a target speed indicator. Your current speed is the white bar itself ( numbers also displayed under it ), but your target speed is different: this is the speed your flight-auto assist computer/mode tries to match at any time if you don’t give any input to the controls.
Ignore the visual design of the HUD for now, it’s just a quick draft madre by André as a placeholder and looks nothing like what it will be in the real game. It’s just used to demonstrate functionality.