How do flights between the islands of Hawaii work?

How long are they and how much do they cost?

Almost all flights are by either Aloha or Hawaiian. Usually about 30 to 45 minutes, but depends on the islands (you may have to connect for some destinations).

They work like any other flight. You can book through them directly or using a site like Expedia or Orbitz, or a travel agent.

alohaair.com
hawaiianair.com
are good places to start.
Most flights are less than an hour, but some of the smaller airports do not have direct flights; you may have to go through Oahu.

Inter-island flights:

How do they work:
Most inter-island flights go thru Honolulu as a hub...i.e. going from Maui to Kona.....Maui to Hono, then on to Kona.....There are few direct flight between islands...check the airline website.

Early morning flights are usually full as residents travel alot between islands. So book in advance.

Also be on time or early, as there are no assigned seating, and standby's are called about 10mins. before departure.
If you are late (less than 10mins) you could miss your flight to standby's.

How long are the flights:
Usually 30-40 minutes between islands.

How much do they cost:
Usually in the $70-75 range. check with local (Hawaii) travel agent...or someone like RobertsOvernighter. However I have seen them listed for $140 on the airline websites.

AAA offers a discout on Aloha so the RT fare or one island to another island should be about $133. You can also use 5000 United Airline miles but those seats are limited so book ahead.

THanks for your help! For a honeymoon, (with about 10 days from the East Coast, spening 5 days on each island) which 2 islands would be the easiest to fly between? Which would be the most difficult?

Don't let the concern of "ease of interisland flights" influence which islands you wish to visit. They are all very easy to get to and leave from, some just more direct than others. It really is only a slight inconvenience to stop in Honolulu if you have to. The layovers rarely exceed an hour. We will be flying from Honolulu to Kona next summer and our last island, Maui, we will have a stop over in Honolulu for 50 minutes.