Pretty sure this has been answered more than once over the course of the thread. There are numerous solutions to this problem and I'm sure if Disney decides they want them to be air conditioned they will have no problem doing so.
http://gondolaproject.com/2012/09/12/how-londons-emirates-air-line-cable-car-powers-cabins/
If Disney decides not to have them air-conditioned, no one will use them. That means they will be open to the elements and as such not run in inclement weather making them a non-practical transportation system. (Not that I would be surprised by them doing this BTW). Also super capacitors are great but tremendously expensive. Unlike London a system in Florida would need a significantly higher capacity power unit to deliver the cooling power required. Consider a 12000 BTU AC unit (and even this may not be enough cooling capacity) consumes 4-5 kWH of energy, super capacitors cost between $2400-$6000 per kWH of storage. Split the difference and say $20,000 per car in power storage alone times the number of cars they have + the actual cost of the car itself, and it adds up very very quickly.