Diesel-electric. They cruise around just under the surface on diesel, with snorkels to bring in air and expel exhaust. But, then they can shut down those diesel engines, fully submerge, and maneuver on batteries for a few days and maybe a hundred miles.
While they are on diesel engines, they are loud, and stuck to the surface. While they are on batteries, they are silent. For the few days that they are submerged, they are quieter than our nuclear subs.
Yeah, they pose a potential threat to a carrier group, but the “proportional response” to attacking a carrier would be the destruction of every naval facility they have, so not exactly a serious threat.
Nuclear is quieter than diesel, but louder than electric. Diesel subs are on diesel for transit to/from their patrol area, and on battery for their short-range patrol. Nuclear subs are much quieter during transit, but slightly louder during a long-range patrol.
Nuclear subs have to continuously pump cooling water; diesel-electrics can shut down pretty much everything that makes noise.
Satellites, drones, and guided missiles all rely on radio emissions for command and guidance. Every ship in the carrier group, plus many dedicated aircraft have SIGINT and ELINT roles specifically dedicated to countering such threats.
While drones and guided missiles do pose a threat to a carrier, the carrier poses a much greater threat to anyone operating such drones and missiles.
Electricity prices in France turn negative as renewable energy floods the grid (fortune.com)
US might send the mighty Dorito if won't behave (sh.itjust.works)