I do not think you can air condition a cable car. Air con uses quite a lot of electricity, where is that power going to come from? Batteries wouldn't be able to charge in time for the short time they are in the stations, compared to out on the wire. Let alone the large amount of extra weight they would add to something that is hanging on a cable. Mains is out the question as there is no way of doing that safely with current systems.
Even the cable car system in Singapore doesn't have air con, I would assume for the same reason. It is not like powering a small speaker, air conditioning is power hungry, a lot of power is required to power the compressors alone, let alone the fans blowing the cool air out.