Commets on these drive trains

[Creator Mat]

i came up with these ideas to present to my team tomorrow any commets on them would be appreciated.
the first idea is a air boat type drive train where a giant fan would drive the robot. Then servo powered flaps would direct the air flow for steering. All this would be on caster wheels.

the second idea is kind of like a snowmobile. in the back there is a mini tank drive that would drive the robot. in the front is 2 swerve wheels that would be used to steer the robot. or the tank drive could do the steering and the swerve wheels would just be casters.