Yes, every separate component is doable. What looks hardest to me is the geometry: every node / drone would not only need to be perfectly synchronized with the rest of the swarm, but also understand its location within it with millimeter precision, in order to time its impulse to do beamforming, or allow locating any received signals. We should assume that near the battlefield GPS is already jammed, so it must be a sophisticated network of laser rangefinders between the drones, plus location data from land stations.

Then, there should be a super-node in a larger aircraft that would receive the data from the swarm and turn it into a coherent picture, run object detection and tracking, etc.