Ongoing wars show how drones are proliferating on the battlefield. In the future, swarming drones will become the dominant modus operandi. Heterogeneous but complementary capabilities of individual swarm members, redundancy, autonomy, and artificial intelligence (AI) make drone swarms superior in operations. In swarms, devices from different manufacturers, coalition parties, and commercial-off-the-shelf (COTS) equipment cooperate. In an operation, a swarm operates as a tightly integrated unit that shares tasks and information among its members. It is crucial that members establish sufficient trust with their communication partners before exchanging additional information. Meanwhile, the human operator is on the verge of falling out of the loop. This chapter constitutes a concept and a vision for smooth and secure onboarding of drone swarms in a military coalition context. This passage presents a scenario, a trust model, and a procedure for onboarding drones in a swarm. The scenario illustrates the dynamic battlefield situation and defines the objectives for this study. The two-layer trust model relies on certificates. The onboarding mechanism supports efficient and scalable deployment of a large number of devices. The purpose is not to present a concrete implementation of the concept, but to reveal challenges, future research needs, and to bring about a paradigm shift in trust management.