This is my husband's two cents on how to do it for less $ -- he is a private pilot:

There are several ways to approach this issue. First being is how much luggage would they be taking. Weight is a key issue if they are to reduce their costs. The less the carry the smaller the plane can be and thus the costs. That being said they also have to consider their comfort level in flying in a small plane - like a single engine plane.

If that works for them then the cheapest would be to contact the local airport and see what flight schools are in the area. Call the flight schools and tell them that they are looking to hire a flight instructor and a plane that holds 4 adults with say 50 lbs of luggage. The schools can tell them if they have an aircraft that can handle such a trip and instructor to spare for a few hours on a given day. That is the cheapest way they could make such a trip.

The flight in this type of plane would take 4 to 5 hours and would run about $55 to $60 per hour for the plane and about $15 to $20 per hour for the pilot. This would be for one way so you would have to double it for a drop off or round trip. Some places will not have the aircraft to do this and others will have more expensive aircraft that will fly faster but of course cost more. The charter services will be expensive compared to this method.