I am preparing for my first PNP mission and am wondering what documentation I should retain for tax purposes. Receipts for fuel and other direct costs are obvious, but is there a flight record form that sending and receiving parties need sign for proof the mission was completed or anything similar? If these questions have been answered in other forum boards I apologize. I searched for the answers unsuccessfully. I have also posted this same question in the "Pilot Talk" forum in hopes to gain advice from active PNP pilots.