Aizawa will be able to find both types of ships out in the ship graveyard. The submarine vessel is mostly a skeleton at this point, but some of its communication equipment is still around, particularly its subsurface VLF (very low frequency) radio tech. It's rusted, but it can be brought back to life with enough time and expertise.

The space vessel has clearly seen better days: most of its cockpit is destroyed, but some of the computer components from its communications station can be salvaged. They're quite high-tech for someone from a modern world, and it won't be immediately clear how to use them or integrate them. More than that, they've clearly been fried and damaged, either by an impact or time, and will also need some expertise and time to bring back to life.