Aerial internet connections will likely be crucial for courier drones and other robotic aircraft, but modern-day cell towers are usually designed to serve people on the ground, not machines in the skies. What to do? Carnegie Mellon researchers might have an answer. They've converted an old ambulance into a full cellular network, and they're using it to test connections to quadcopter drones carrying phones on their stomachs. As it turns out, in-air wireless links aren't that reliable using current technology -- you need to point the antennas upward, and the signals propagate differently above a cell site than they do below.