Big Island of Hawaii: The Big Island's two airports are in Kona and Hilo. Most people rent cars or get shuttle service from their resort (not usually for free). The approximate taxi rate is $3 for the initial 1/8th mile, plus $3 for each additional mile. SpeediShuttle serves the Kona Airport only.
Kauai: All commercial flights use the Lihue Airport. Taxis cost anywhere from $17–$20 to Wailua–Waipouli, $35–$41 to Poipu, or $72–$95 to Princeville–Haena.
Oahu: Honolulu International Airport is 20 minutes (40 during rush hour) from Waikiki. Car rental is mostly by van pickup across the street from baggage claim. An inefficient airport taxi system requires you to line up for a taxi wrangler who radios for cars ($40–$45 plus 60¢ per bag to Waikiki). Other options: TheBus ($2.75, one lap-size bag allowed), and the Roberts Hawaii Express Shuttle ($16 per person). Uber and Lyft also serve the airport.
Maui: Most visitors arrive at Kahului Airport in Central Maui and rent a car. If you don't want to drive yourself, SpeediShuttle costs $67 per couple to Kaanapali, $47 to Wailea. Taxis cost anywhere from $20 to Wailuku, to $79 to Kaanapali, $45 to Kihei, $69 to Lahaina, or $50 to Wailea.
Lanai and Molokai: Ferries and air taxis are available from Maui to Lanai (no ferry service to Molokai any longer); airport shuttles are available on Molokai, but not Lanai.