Re: Thunderbird 2?
Imagine not having to file in to a small metal tube, and instead be seated in a land-based boarding area (a bit like Heathrow) - still shaped like a tube, but without the massive inconvenience of the wait.
Then, to save time, instead of having to wait until the flying bits are attached, the tube can have its own wheels so it can roll to its destination all by itself. You can choose to use "rubber" wheels and stuff called "tarmac", which is abundantly available, allowing you to be quite flexible in choosing a destination, or the wheels can be made of steel requiring them to roll on "tracks", also made of steel. The latter option offers less flexibility but higher speed. The tubes can even be within bigger, underground tubes, again on rubber or steel wheels, so that no-one above ground notices you're moving