I don't know about you but I've found the lack of air traffic over North London very strange - combined with the unseasonably warm weather and almost non-existent breeze makes the absence of vapour trails even wierder than usual.
The grounding of almost all European flights also serves to remind us how much of our lives relies on the knowledge of others:
Until now, the simple act of airtravel hasn't required any of us to think very much - we haven't had to think through the mechanics of airtravel - the physics of it for example - we've taken it as read. Other folk must know, I presume, but not me.
Nor have many of us had to think about the practicalities in the sense of building a flying machine or flying it or where from and where to - we've again relied on other people
Nor have we had to develop an expertise atmospheric meterology - to understand when it might be safe again to take to the sky courtesy of others - no, we're relying on other people like weather forecasters and so on.
The point being is that modern life is about each of us relying on knowledge we don't have (or need to have); modern life is enabled by our ability to encode knowledge and experience in the brains of others - others often long dead; in the modern world, none of us has to know much really.
In other words, our ability to learn from others and to access what other people know is one of the things that makes us so successful. And all of this before the web came along!
Imagine if - as other primates mostly do - you had to learn all this for your self...