The wide-open space is a departure from Heathrow's older terminals
Before the official opening of Heathrow's Terminal 5, members of the public were recruited to help test the £4.3bn building in an attempt to iron out any problems. The BBC's Matthew Shaw was one of them.
Not being the most relaxed traveller in the world, it seems a bit mad to spend my spare time in an airport.
I am one of those weird people who arrives at the terminal a day before my flight, checks for my passport and boarding pass every five minutes and won't relax until those cabin doors are finally cross-checked.
But this time was different. I had volunteered for a different kind of experience. Along with 2,000 other would-be passengers, I was trying out Heathrow's Terminal 5 for size just days before its royal opening.
For weeks now, armies of men, women and children have been pretending to be British Airways customers as it conducted a series of trials to test out the UK's newest and biggest air terminal.
After booking my place online, I am told to meet at a hotel for breakfast.
Dozens of scanners
I am with a few hundred others, most of them cub scouts and guides. It's more like a noisy jamboree than a serious dress rehearsal for such a high-profile building.
We hit our first queue of the day to be given our passenger profiles.
My luck is in - I am now to be known as Mr E Brooks and I am due on the 1145 to Hong Kong. I do a lot better than my friend - he is now called Miss Dianne Frankfurter.
But now the bad news - I'm flying economy. I'm not even at the airport yet and I'm already fooled into thinking I am actually going somewhere.
British Airways says the 96 check-in kiosks will mean no queues
I have been told I've no baggage to check in - which leads to much discussion about how I could last in the Far East with the contents of a plastic bag.
I spy a Club Class ticket-holder but breathe a sigh of relief when I am reassured that the executive lounges are not yet open.
A short bus ride and I'm finally at the terminal. It's truly enormous but not as noisy as I'd feared.
The departure area is open and bright, with no sign of those dreadful Heathrow carpets.
I spend a few minutes checking myself in, a member of staff pretends to flick through my truly fake passport and I am off to security.
There seem to be dozens of scanners so it's not long before I'm in the cavernous departure hall.
If the shops were open I'd never leave - but it's off to gate 10C to climb aboard a bus to my flight. At the start of the day we were tantalisingly told we might actually be boarding a real plane - which would push back off the stand and taxi for at least 10 seconds.
No such luck - I'm on a bus tour of the runway and the nearest I get to Hong Kong is the distant sight of a Cathay Pacific plane.
Back to arrivals and we're told we're now transferring to a flight to Nice.
Never mind Kowloon, I've got the Cote d'Azur to look forward to now!
I stroll around the empty corridors and start the whole journey again. The wait for my transfer flight is a little bit long but thankfully I don't have to go through the pretence of boarding again.
In fact I'm told to go straight to passport control where UK border staff wave us all through with a smile.
In fact the whole experience is probably a bit like the heyday of glamorous air travel - no queues, no borders and no hassle.
So armed with a gift, I'm sent packing. I'm relieved to be home in one piece and longing to sleep off the make-believe jetlag.