Why are the tyres of aircrafts made of conducting rubber?

1. So that the charge accumulated on the aircraft in flight, by rubbing the air, can easily be transferred to ground on landing.

2. So that the charge accumulated due to the operation of various electronic equipments in the aircraft in flight can easily be transferred to ground on landing.

The electrostatic potential doesn't depend on which of the following 

(1) It depends on the charge

(2) It depends on the endpoints of the path through work done

(3) It depends on the path taken for the work done 

(4) It depends on the amount of work done