Insects that predate aerially usually contrast prey against the sky and attack upwards. However, killer flies (Coenosia attenuata) can attack prey flying below them, performing what we term 'aerial dives'. During these dives, killer flies accelerate up to 36 m/s2. Although the trajectories of the killer fly's dives appear highly variable, proportional navigation explains them, as long as the model has the lateral acceleration limit of a real killer fly. The trajectory's steepness is explained...