One drone lifts up into the sky at a shopping centre on the outskirts of Dublin, then another. They rise to 70ft (21 metres), tilt forward and zip away in different directions, each carrying a paper bag. On a sleepy morning in the Irish capital the takeoffs build to a steady one every few minutes, with barely anyone glancing at the constant stream of aircraft buzzing back and forth. “No one’s looking up – no one ever looks up,” says the man responsible, Bobby Healy, the founder of the Dublin startup Manna Aero. People probably should take notice, because the...