I have a client I have trained for almost 2 years who travels every 8-10 weeks internationally for 2-3 weeks at a time. I have been providing him travel programs, but he has expressed interest in having me travel with him to train him in person on these trips. I am at a loss in how I would charge for this, he would be paying for my flight, but I am also giving up sessions with other clients during this time. Does anyone have a similar situation, and how do you charge?