The world’s skies are becoming crowded, posing a risk to airlines as rockets, drones and, in the near future, “flying taxis” begin to use airspace. The huge number of new rockets – pioneered by Elon Musk’s SpaceX – is set to exacerbate the problem as the growing commercial space industry will share airspace used by tens of thousands of passenger planes. Meanwhile, drones and the expected emergence of electric vertical take-off and landing aircraft (eVTOLs), so-called flying taxis, are set to complicate the management of the lower levels of airspace through which planes take off and land. The number of…