There are hundreds flying drone brands. But there isn't many...

There are hundreds flying drone brands.

But there isn't many underwater drone brands.

Going up is easy as it's empty, going down is hard as you deal with enormous amount of water pressure.

Also in terms of depth of addressable market, no, you can't fly drone anywhere you want, as matter of fact, you will find less and less within inner city allows flying drone, regulation will catch up soon.

Underwater drone can be a huge part on sport like recreational fishing.