You'll need to rent a car to get around each island, but make sure to reserve early as they can sell out during peak seasons. Inter-island flights are also available and will be necessary if you plan on visiting multiple islands. Expect to pay around $100 per person each way for inter-island flights depending on the airline.
If you have more time, consider adding a day trip to Lanai or Molokai from Maui. If you have less time, it's recommended to visit only one or two islands to fully experience all they have to offer. Make sure to pack comfortable shoes and clothing, as well as reef-safe sunscreen and bug spray. Also, be aware of the weather conditions and check trail and beach closures before heading out.
The main airport in Hawaii is the Honolulu International Airport (HNL) located in Honolulu on the island of Oahu. Other major airports on the islands include Kahului Airport (OGG) on Maui, Kona International Airport (KOA) on the Big Island, and Lihue Airport (LIH) on Kauai. All airports are located within a short driving distance from major tourist areas.