If you haven’t been to the United States for a while, expect changes and they will be obvious when you step out of the plane and onto American soil.

You will notice in airports dishevelled people, panicking with glazed eyes, ungainly running along concourses, some cracking their ankles in stilettos, others repacking their dropped bags as they race against time.

They’re forced to forget outward appearances as flights are called followed by announcements of those who haven’t made it to the gate. And that’s through no fault of their own. Security checks are made upon security checks, it’s as if the first scanner was inadequate.

Just as the security cordon’s cleared and you feel free to breathe a sigh of relief as you repack after the last scan, you begin picking up your step as the gate closure draws closer. What’s this, another even larger queue with everyone on it checking their phones as watches?

The intercom blares out another spate of missing passengers and final calls as more panic sets in.

The passengers are herded like sheep, 10 at a time, but the heavily armed stockman’s in no hurry. As you slowly edge to the selected 10 you pluck up the courage to ask what this is all about, you’ve been checked at least three times already.

Step to the right, the order’s barked, it’s the canine check. The Dashound looks extraordinarily calm amid the chaos around him, giving the anxious passers-by an ever so cursory sniff.

The calm of the cab on the way into the city is a welcome relief, you wonder how many people are left waiting at the airport for the next flight, their booked one will have arrived at its destination by now.

But the chaos isn’t confined to the airport, this is the United Nations Leaders’ Week where this year 140 of them have descended on the Big Apple to grind Manhattan to a standstill as roads are closed off to take them to and from their luxurious digs, usually no more than a kilometre away.

If you are in the city to cover the event, like me, you tend to put the airport chaos into some sort of perspective. If you assume you’re seen as a terrorist you’ll find it easier to cope with. Orders make little sense, even though they’re politely issued but always without explanation.

You can’t take that coffee through there, I’m told. Inquire why not and the order’s simply repeated. When you see a delegate, their word for an official, doing exactly the same thing and you again inquire. You can’t take that coffee through there, is the only explanation.

So where do you put it? There’s not a rubbish receptacle in sight. You put it on a pile of other coffee cups, so it’s clearly, rules rather than the environment that’s of prime concern.

As much as it doesn’t make sense, you’re forced to grimace and bear it, not unlike the United Nations in a way which will this week be concentrating on the environment.