Something also planned for New Zealand too: https://www.oceanflyer.co.nz/
https://www.stuff.co.nz/business/128397643/transport-revolut...
"Ocean Flyer’s seagliders would be able to fly people between Wellington and Lyttelton in an hour for $60 a seat, or between Auckland’s Viaduct Harbour and Whangarei in 30 minutes for $30, Aslam forecast."
Feels pretty speculative
It's too far to use the Harbour infrastructure at either end. You would have to build a pier on the southern side of Wellington (say Island Bay) and then use New Brighton pier. That works out to about 295 km.
With only 300km range, it's hard to find good routes in NZ.
From what I can tell, the design is still in development. The 300km number is probably more of a conservative estimate than an actual range. The Ocean Flyer team might be gambling on the real-world range being long enough for the Christchurch-Wellington route.
That said, given how much the current ferry has issues - maybe this is just as safe.