https://patents.google.com/patent/JP2018522782A/en
https://patents.google.com/patent/WO2022214651A1/en
https://www.sciencealert.com/boeing-s-latest-patent-reveals-a-drone-that-can-transform-into-a-submarine#:~:text=Boeing%27s%20latest%20patent%20application%20is%20yet%20more%20evidence,of%20the%20ocean%20and%20continue%20its%20journey%20underwater.