What will it take for drones, and the whole associated ecosystem, to take off? Arguably, infallible C&C channels for safe and autonomous flying, and high-throughput links for multi-purpose live video streaming. And indeed, meeting these aspirations may entail full cellular support, provided through 5G-and-beyond hardware and software upgrades by both mobile operators and manufacturers of these UAVs. In this article, we vouch for massive MIMO as the key building block to realize 5G-connected UAVs. Through the sheer evidence of 3GPP-compliant simulations, we demonstrate how massive MIMO can be enhanced by complementary network-based and UAV-based solutions, resulting in consistent UAV C&C support, large UAV uplink data rates, and harmonious coexistence with legacy ground users.