Flight
You can also look up Kapalua Airport. It is on the Lahaina side of Maui but I do not believe connects with any car rentals. It is a very small airport.
Travel Note
Please stay on the Lahaina side of the island. Traffic is horrific in the afternoons and would hate to not have you present because someone saw a whale and stopped on our lovely 2 lane highway. Towns to stay include: Lahaina, Honokowai, Napili, Kaanapali, Kapalua....If you look on the map, it will be on the far left side (not the lower left) of the island. Basically Lahaina town and north of it. If you decide to stay north shore or Kihei/Wailea, PLEASE give ample time to travel. A drive can go from 40 min to 3 hours very quickly. If you have hotel or AirBNB ideas you want to run past me, please feel free.
Flight
These airlines tend to run deals. I believe there will be a Fare war starting at the end of Oct so keep an eye out. Hawaiian does have a direct flight to Oahu from JFK, then a 30 min flight to Maui. I know Delta and United offer direct flights from CO. All of them have direct flights (I think) from the entire west coast.