Bonza has its AOC

[43Inches]

Again you are purely thrusting in line with current technology.

You are not getting something for nothing with displacement, as you have displaced the water to carry the load, the ship has to be able to displace that water constantly and move through it efficiently to provide the reliable transport aspect. The environment in which the ship lives is also corrosive to its existence and all it's parts further adding to the complexity of the cost of operation. Displacement is just a well known and easy to work with concept. The problem now is the lack of speed in the method due to hydrodynamic drag being far greater than aerodynamic drag, fly a float plane and you will learn the difference very quickly or end up inverted. Oil producers get around this by having 'product' constantly in motion, and tankers can be diverted en-route to a more profitable destination should that need arise, which is fine if you have one product type.

There is still a lot of engine improvements that can further reduce fuel consumption markedly for aircraft, and allow hotter burn without mixing air to prevent melting hot sections which is the current issue with efficiency. Obviously the metallurgy or ceramics needed are still in development to make them capable of mass production or cheap enough to be viable. But like Battery technology this is constantly evolving, with every new generation of aircraft becoming more efficient in terms of energy use. So not only is scale increasing but there are also huge gains in efficiency happening.

Shipping is already at a size wall for a lot of routes as you can only go so big before the existing canals are too small to navigate. Smaller non specialized ships are already uneconomical and becoming rarer.

A little over 20 years ago I was party to acquiring an ex-Sydney ferry to operate Port Phillip bay, the vessel was in ok condition but required much work to get it to the state we needed it in for the task we wanted. After a survey was completed and costs added up, the static costs of just keeping it afloat without being mobile exceeded the break even costs without it even being operationally crewed and capable of movement, let alone sailing out on the bay. It was much easier to let somebody else try that gamble and it definitely did not pay off for them.