This paper presents a preliminary development on a guidance algorithm capable of landing a fixed-wing UAV on a moving platform. The problem has not been investigated thoroughly by the community where almost all of related works are applications of either helicopters or multirotors. The problem is challenging because it demands position, velocity, and attitude to be matched simultaneously at touchdown. We formulate the problem as a minimum time optimal control problem and solve it using the pseudospectral optimal control method. We found that direct-lift control is a key element to successfully match position, velocity, and attitude simultaneously at touchdown. Our approach can handle steady wind and can also handle mildly maneuvering platform scenario. The algorithm is tested with various initial conditions and also tested in a receding horizon manner. The method is too slow to run in real-time. However, it reveals many challenges unique to this problem that must be overcome in future research.