Beyond the wingtip is a clear blue sky, exactly the same kind out of which tragedy arrived a year ago.

It is September 11 and I'm flying into New York, America's capital of brashness but which now has a hole in its heart.

Security today has been tight as expected in a country on "orange alert" (one down from "red alert") but as I have hopped from Los Angeles to Seattle then Chicago these past three days the flights have all been full. In the past days I have seen About a Boy three times with the sound off, flown over glorious patchwork fields of brown and green, soared over thick forests which have glowed in the autumn light, and looked down on cloud-filled canyons. America the beautiful.

But on television and in newspapers there has been talk of war, "regime change" has entered the common tongue, and as the anniversary of September 11 approached there was a palpable tension and uncertainty. My friend Karen in Chicago and her boss Dave are both going to work from home today rather than go into the office.


Yet flying is as American as a side order of fries and "you're welcome", and so the planes, as expected, have been full.

But today, the anniversary of the iconic "9/11", is very different.

At Chicago's O'Hare International - usually the busiest airport in the world - the polite young man waving the electronic wand over me says, "It looks like midnight in here."

He's right. At 7.30am the concourse is deserted.

The woman at the United Airlines counter says, "If you want a window or aisle seat that's fine, we've got a whole plane for you. In fact, pick a row."

Of course, logic tells us this is probably the safest day of the year to fly. We undergo two thorough security checks - "and now if you could take off your shoes sir, I'd like to check them and the bottoms of your feet" - and everyone seems to be watching each other. I feel sorry for that Muslim family on their way to Los Angeles.

There is the presumption that terrorists will strike today. Yet by its very nature terrorism is unpredictable. Why September 11, 2001? Why not?

But a lot of people aren't buying the safety argument and have put off flying for another day.

Minutes before take-off the security and airlines staff outnumber passengers by two-to-one. There are fewer than two dozen of us flying to New York this morning.

The guy in the red shirt opposite puts down his Dean Koontz novel to cross himself as we taxi to the runway. Those who have arrived in pairs fall conspicuously silent.

Our captain comes on the intercom just before we race down the runway to tell us because of the significance of this day there are security restrictions in place.

We can't leave our seats in the half hour after take-off or the half hour before landing.

"If you get up at that time," he says, "Well, we're gonna take that pretty seriously. So sit back and relax and take a good look out the window at our beautiful country."

We lift off. Chicago's Sears Tower - the second highest building in the world after the Petronas towers - pierces the skyline to our right, the broad expanse of Lake Michigan ahead.

Somewhere over Michigan our smiling steward gives us breakfast boxes. It all seems alarmingly normal - but it's not. One of the crew comes over the intercom to remind us of this tragic day in American history and how "we got through that day and the year that followed, and we can get through these days, by supporting each other".

We are invited to reflect on the day and the lives lost, then the steward returns, offering more coffee.

It was on just such an otherwise ordinary day, on ordinary commuter flights like these, that tragedy came out of a clear blue sky. For even the most cynical, it is a chilling thought.

We approach New York and the pilot dips the left wing towards that dusty hole in the ground - Ground Zero - as a mark of respect. Below us are Central Park, the beautiful Chrysler Building glinting in the morning sun, the Statue of Liberty ... Ninety uneventful minutes after leaving Chicago the guy across the aisle is crossing himself again and we have taxied up to the walk bridge at LaGuardia.

"Welcome to the great city of New York," says our captain. "Sixteen minutes early."

* Tomorrow: In a New York State of Mind, Graham Reid reports on the mood of the Big Apple.