There is a big problem standing in front of transport. On the one side, we need
our machines hovering or standing on the ground. This can be achived by using wings
or water underneath the machine. But water will cause big friction so it's better
to use solid ground for standing. Although water or liquid with appropriate density
can be used for building multi-level roads.
By the way, bigger levels of speed can be achived when moving far away from the ground, because density of air decreases. But we can use advantages of higher levels by by building tunnels for trains. These tunnels shall be isolated and connected by tubes with several-kilometer-level of atmosphere.