Ours, IMO.
Recent disclosure Salvatore Pais patents & published articles.
Some:
Hydrid Craft Using Intertial Mass Modification Device–article–pais2017.pdf
Room Temperature Superconducting System for use on a Hybrid Aerospace-Undersea Craft–article– pais2019.pdf
US10144532-Pais-Craft Using An Inertial Mass Reduction Device.pdf
US20180229864A1-Pais-High Frequency Gravitational Wave Generator.pdf
US20190058105A1-Pais-Piezoelectricity-Induced Room Temp Superconductor.pdf
Abstract of paper on Hybrid Craft
Can't find the image of the undersea "UFO" craft emerging from underwater at high speed but believe it was of this general type, and not "aliens" either.