Millimeter-wave　(mmWave)　massive　multiple-input　multiple-output　(MIMO)　offers　a　promising　technique　to　fulfil　the　high　data　demand　and　connectivity　of　the　Internet-of-Things　(IoT)　and　5G　communications　because　it　owns　valuable　and　unknown　spectrum　resources.　Using　massive　antennas　with　recently　introduced　drone-enabled　aerial　computing　platforms,　named　unmanned　aerial　vehicles　(UAVs),　can　cast　high　energy　consumption　if　fully-digital　precoding　is　employed　at　the　UAVs.　Using　hybrid　precoding　at　a　UAV　can　reduce　hardware　complexity　and　energy　consumption　but　is　challenging　with　a　need　for　joint　optimization　of　three　precoding　matrices　at　the　UAV　(sixth-order　polynomial　objective　function).　In　this　paper,　we　propose　to　decompose　the　original　UAV　hybrid　precoding　challenge　into　three　subproblems　and　develop　a　coordinated　descent　optimization　(CDO)　algorithm　to　solve　the　three　problems　recursively.　In　addition,　the　convergence　and　complexity　of　this　new　technique　are　analyzed.　Numerical　studies　indicate　the　improved　effectiveness　of　the　proposed　solution　over　existing　solutions.