I am planning a day trip to Hilo on Oct 27 and would like to know how long in advance should I book a helicopter/plane ride? I don't want to book in advance just in case my flight from HNL to ITO gets cancelled or delayed and I miss my heli flight and lose money. I was hoping to be able to fly in and pay on the spot for a ride and if there are no seats hire a car and drive to the park. I am planning to fly in at 2:41P and then take a 4/4:30 flight by either of the foll:

http://www.hawaiiislandhoppers.com/

http://www.hawaiidiscountactivities....age=1&island=1

http://www.hawaiiactivityworld.com/b...icopter_tours/

Is this plan realistic? Thanks.