Are you up for an adventure? It is a small aircraft that seats about 10-20 people and very noisy. However, they fly low and slow and you might get to see more of the islands. I assume that the $140 more is for all five people and it is not worth the extra cost unless you are looking for a little fun. However, if anyone doesn't like small planes, than forget about it. The three kids might enjoy the SuperFerry and the cost on that is a lot cheaper than flying. However, it leaves Oahu around 6:00 a.m. and 3:00 p.m. and twice a day only four times each week. So, their schedule may not work for you unless you are staying overnight on Oahu and traveling the next day.