International airlines offer "missionary fares" by reserving a block of discounted seats for humanitarian and missionary travelers. These fares offer lower prices that don't increase for last-minute bookings, reduced or waived change/cancellation fees, and extra baggage allowances. They are best booked through a travel agent as not all airlines allow online booking and agents can access additional savings. However, the discounted seats are limited and not available on all flights. The fares can be used by anyone traveling for a registered non-profit, including churches, mission trips, and individual missionaries.