Yes, to rent a car is the easiest, although there are walking plank ways and city buses shuttling between scenic spots. You can consider rent a bus from the airport to hotel, to Jiuzhaigou Huanglong airport. Usually, people will contact a driver before going through friends or agent. It is a bit more expensive to find a van at the airport. You can take the airport bus to the town and then find a van in the town. The price is different relying on where you plan to go. Songpan-Huanglong-Jiuzhaigou: about 700yuan