@TheJamsh I was thinking on the 3D case, maybe a fast solution would be select a number of cells to search for N steps above and bellow by M distance each step. This would reduce the overhead to do it completely for the whole plane projected in 3D, reducing to the interest areas only for a certain depth. The precision would be adjusted by the steps * distance affecting only the selected cells.
I am too looking for an application for aerial/space combat, and that would be great.