Swarm Aero has raised $35 million in its Series A, led by Two Sigma Ventures and Silent Ventures, and plans to more than double its headcount by the end of the year. The California company is developing large, swarming drones capable of carrying missiles, electronic warfare payloads and cargo alike. It has completed preliminary design for its Group 5 drone, which is expected to take off heavier than a whale and will be first flight within two years.