Unless you:
* Rent the aircraft & fly it yourself, or
* Share all costs equally between all on board (including the pilot)**, or
* Find an owner who's willing to supply his aircraft for no charge,
then your only alternative is to charter an aircraft with a certificated air carrier. To do anything else is illegal.
**Share costing can be iffy, in the eyes of the FAA. All parties must have a legitimate reason for the trip.