Flight
Being this is a destination wedding, the only airport to fly in to get to the Big Island will be the Kona International Airport (if you're not already coming from another island in Hawaii).
Travel Note
The wedding will take place at Puakea Ranch, which is the north side of the Big Island. This is approximately 45m-1h of driving from the airport itself. The venue itself will have plenty of parking to accommodate those that will be renting cars to zip around the island.
Travel Note
Hotels are really expensive on the island, so I would suggest looking at rentals first for a more budget-friendly option.