My wife's company has a team of engineers who will need to travel numerous times over the next year approxomately 250nm away. They want me to fly them and have asked me to look into what it would take. I would be volunteering my services as pilot but need an airplane. Is there any way to do this with them renting an airplane? Is the cost of rental considered "compensation"? Is it considered "holding out"? Any help would be great.