With all the capacity shortage issues at big airports and all the arguments for new runways etc with politicians, residents and green campaigners getting in the way and nothing getting or done or taking years to do anything why not switch to something more radical?

For somewhere in the UK, Heathrow and Gatwick with their endless capacity issues could move many of their flights to Brighton and a large seaplane airport could be built where planes could just take off from the sea. It a great idea IMO.
Of course normal airports and normal planes would be kept but every sea or riverside town or city could have its own seaplane airport which would require no runway resurfacing etc, would be cheaper to run and would not require tarmac for runways.

Of course it will never happen but its fun to speculate.

For example if I wanted to fly from St Louis to New York I could fly on a seaplane from Mississippi River over to the coast of Long Island or to the hudson.
Most of JFK's flights could take off and land from sea of Long Island's coast and most of LGA's flights could move to the hudson river.

Too many weather issues.

I think speed would also be an issue, and possibly fuel consumption. Are there any retractable float seaplanes? Jet seaplanes?

I would expect maintenance costs and downtime to be higher too, especially if salt water ports were used.

Not really a "seaplane" but Beriev makes the Be-200 for fighting fires. It's pretty cool.

http://www.youtube.com/watch?v=E858ja856Cw

Seaplanes are alive and thriving up in Vancouver British Columbia.

And in Bangladesh. You never know what's floating in the landing strip though.

One landing would likely reduce your affection for them.

Crowded gates and runways? Well, not as much of a problem as keeping the locals in their multiplicity of small watercraft clear from the paths seaplanes would require for take offs and landings.

Having had literally hundreds of flights on seaplanes. I find the landings were better then any land based plane I had been on.
How I miss Chalks ocean airways.

I love that flight from Vancouver to Victoria.

Perhaps the Spruce Goose ?
It is sitting there unused in the museum in Oregon...

It'll need new engines to get enough altitude. There's quite a couple of Martin Mars in service in B.C.

Occasionally, you see a Twin otter sinking for whatever reason.

Uh Oh

Both the US and Russia abandoned their large seaplane tests and plans some time ago.

Major issues include weather and corrosion. Other issues include the fact the most efficient aircraft design is not one with a ship hull adaptation for waterborne, takeoffs, landings and taxiing; this alone, given the cost of fuel, would likely make use of large seaplanes prohibitive.

That having been said, there are places, usually not the kind that would have hundreds of passengers arrive or depart at once, where waterborne aircraft are just fine - which is why there are many (generally smaller, up to "twotters" or the like,) in use.

No sea in Dallas. I would be out of luck.