Would the 'Saunders Row Princess' flying boat have solved the additional runway question?

Actually we tried that about 80 years ago. Flying boats were seen as having two advantages, first not having to build expensive runways and airports, but also being safer because they could float on the ocean in case of mechanical failures.

But I think it turned out that flying boats were not nearly as efficient. Fuel efficiency is -the- most important consideration in new aircraft designs. In fact it's really about the only reason we need new designs for large passenger aircraft!

1

Not really.

Firstly, there are places where flying boat cannot go; landing in the center of Denver, for instance.

Second, getting to a terminal from water, and transferring flight would be somewhat nightmarish.

As would be in between flights ground maintenance and servicing.

Also, flyng boat have a maximum wave height they can be operated from, so either weather has to be mild, or the take-off and landing zone has to be protected from the open water by a wave breaker of some sort.

Operation in wintertime would also be problematic...

No

The plane has to be built too strongly to be able to land on water rather than land and thus is too heavy

When the water is rough they cannot land

They were tried and used when fewer people were flying. For the above main 2 reasons they will not work now

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