It takes a tremendous amount of driving force to push a vehicle through the air
at high speeds (say, 300+mph). If the vehicle is wheel-driven, lack of traction
is likely to be a major problem, unless addressed adequately. It's not easy to
do so.
Providing a sufficient downward force--to prevent wheelspin--on the drive
wheel(s) can be done two ways--with weight, and with force induced by the
vehicle's propulsion system.
The first way is to design and build the vehicle such that plenty of weight is on
the drive wheel(s). If the basic weight of the vehicle isn't enough, ballast can be
added. Adding ballast means that there is more mass to accelerate. Generally,
this isn't a big problem if the race course is plenty long.
The second way is to add downward force to the driving wheel(s) by non-weight
methods. An example of this is to aim the exhaust pipe(s) upward, or to have
some kind of powered "fan(s)". I don't know whether a fan is permitted for this.
Another way that appears to be permitted is to use aerodynamics to create a
downward force on the drive wheels. For decades, dragsters and other race
vehicles have been doing this, using "spoilers" or "wings". These do, however,
make a vehicle less smooth, aerodynamically, for forward travel, and thus requires
power. If there is plenty of power available, then it may not be a major issue.
Lots of experimentation is likely to be required.
It appears that the Carbinite LSR car has adjustable spoilers or wings between the
body and the rear wheels. Here's the web address (you may need to copy and paste):
http://landspeedevents.com/blog/carbinite-lsr/