I often think of this one as well.

It parses fine really, there is a (possibly empty) set of things that float in the air, and the spaceship is one of them, but bricks are not. It's not nonsensical, it's just a creative twist on a common idiom ("in much the same way a brick does") that's so unexpected it seems silly.

I also think of the later books where Arthur perfects the art of falling and missing the ground sometimes.

I love Douglas Adams

Some of my favourite Douglas Adams ones:

Let's think the unthinkable, let's do the undoable. Let us prepare to grapple with the ineffable itself, and see if we may not eff it after all.

The major problem—one of the major problems, for there are several—one of the many major problems with governing people is that of whom you get to do it; or rather of who manages to get people to let them do it to them. To summarize: it is a well-known fact that those people who must want to rule people are, ipso facto, those least suited to do it. To summarize the summary: anyone who is capable of getting themselves made President should on no account be allowed to do the job.

For a moment, nothing happened. Then, after a second or so, nothing continued to happen.

God's Final Message to His Creation: 'We apologize for the inconvenience."

Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so.

It can hardly be a coincidence that no language on earth has ever produced the expression, 'As pretty as an airport.'

Tagging on, since my favorite quote is also from Douglas Adams:

This is rather as if you imagine a puddle waking up one morning and thinking, 'This is an interesting world I find myself in — an interesting hole I find myself in — fits me rather neatly, doesn't it? In fact it fits me staggeringly well, must have been made to have me in it!' This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, frantically hanging on to the notion that everything's going to be alright, because this world was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise. I think this may be something we need to be on the watch out for.

• Douglas Adams, The Salmon of Doubt

It's stuck with me as a perspective I have. It's up to you to make things happen the way you want them to, and certain things shouldn't be taken for granted.