How ships fly from node to node?

Is it through combustion? They point their ships to another node and the initial outburst of combustion make the ships go to that direction and then the lack of gravity keeps their movement and direction until arrival?

Is it by using portals that take the ships through "hyperspace"? That would explain why ships can't attack each other at star lanes, only at nodes. So Star Lanes are technically lanes where hyperspace travel is possible? And Warp Drive is the use of warp travel that is not limited by star lanes?

What about Vaulter's portals? That is the game fastest transportation method... But I have a theory that the Academy has a very limited portal technology, since their heroes can be assigned from one system/fleet to another system/fleet in the other side of the galaxy in one turn. But they can only do it with their ship, not an entire fleet. The Vaulters scientiphic genius discovered the technology to do it to an entire fleet...

This stuff is physically impossible, don't think about it, just appreciate how cool it is. If you want ingame explanation point no further than the endless, they probably set most of this stuff up.