projective kinematics; special $s$-parameter motion
The paper contains the solution of the classification problem for all motions in the complex projective space, which have only plane trajectories. It is shown that each such motion is a submanifold of a maximal motion with the same property. Maximal projective space motions with only plane trajectories are determined by special linear submanifolds of dimensions 2, 3, 5, 8 in $GL(4,C)$, they are denoted as $R, E_1, ..., E_6, S_1, S_2$ and given by explicit expressions.
 J. Tölke: Eine Bemerkung zu den Projektivbewegungen mit nur ebenen Bahnkurven
. Arch. der Math. 33 (1979), 279-282. MR 0559548