The world’s skies are becoming crowded, posing a risk to airlines as rockets, drones, and “flying taxis” in the near future 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 passenger planes is forecast to grow by a third to more than 36,000 aircraft by 2034, according to consultancy Oliver Wyman. By that point, they will be sharing the skies with more than 10,000 eVTOLs, according to Bain, and thousands of rocket launches.