I have to admit, that how this game's jetpack works is exactly the same as a game called Giants: Citizen Kabuto. You can see the pic in this link
I doubt if the dev were making it using that exact system as a reference.
In Citizen Kabuto, the Meccs received an upgrade from the Smarties(Ugly big head people), that adds an immediate boost for the jetpack while in mid-air. Enables the player to fly much higher/further, you can see the small shiny sphere besides the jetpack meter to the bottom left of the pic above.
While the jetpack in Satisfactory is pretty much, imo, a clone to that system in Giants, I wish we can have that boost addon while trying to reach to highground, or simply go much further when launched from an MK5 conveyer belt
Here's how it works:
1.It's an addon to the existing jetpack, an upgrade, you can see it as Jetpack MK2 or Jetpack Plus
2.How it works is that while you are consuming fuel and flying in mid-air, press a certain key to activate the boost.
3.This will give you a sudden burst of speed, which adds an additional velocity to whatever direction you're currently heading
4. This boost can only be used once during each flight, has a cooldown and can be recharged short after you landed.
5.Doesn't neccessarily have to cost addition fuel to activate this boost.