Bury this creepy idea, please

Now that the stories about Rome's Jewish catacombs have died down (sorry), you can prepare to hear about Jerusalem's Jewish catacombs. Yes, that's right. J-m is running out of burial space and one of the proposals is to bury people in underground tunnels,

sort of like ancient catacombs but with modern ventilation, lighting, elevators, ramps and even tastefully decorated waiting areas. The tunnels, 15 meters wide and seven meters high, would be large enough not to be claustrophobic. They could be built in stages, starting with one story and then adding others as needed. There would be conventional burial in rows along the floors, similar to what is offered today, as well as burial in niches in the walls. Families would be able to choose the kind of burial they prefer.

Hmmm. Overground, I'd guess.
On the plus side for cohanim, flying over these catacombs won't be a problem...