It may have begun days, even weeks before. But the feeling accelerates when those doors are closed with a final clunk – 'ready for take-off' – and you listen to the strange sounds.
There's the 'ping, ping', like the prelude to all those airport announcements you've just ignored through a fog of anxiety, and the other one, the sickening brake-screech. The last bit of safety announcement fades. And as you taxi down the runway and head from terra firma to the unfamiliar element of the air, it's clear you're not alone in your fear of flying.
Some people are over-intent on their books and magazines, some close their eyes, a few chat for Britain. As a journalist put it, in each cosy aeroplane row of three, one person would rather be somewhere else. Anywhere else.
As a fearful flyer, albeit a frequent short-haul flyer with family in London and a seasonal desire to escape to places like Paris and Italy, I've wanted to conquer this phobia for a long time. Since I was 10, in fact, and took my first flight to Africa with my also nervous mother. We were heading to a tricky domestic situation and I picked up her ambivalence.
With gaps in my flying career, I've attempted to tame the thing by desensitisation and latterly avoidance – for around 20 years first time round, then eight. But nothing worked.
So the news that coaching psychologist Alison Clarke had started a fearless flyers' course (note the clever rebranding) out of Belfast City Airport with the help of one of Aer Lingus' top pilots, Capt Harry Brady, made me think again.
Could I make my white-knuckle rides something more pleasant and maybe one day resume long haul to revisit Africa and head for New York, somewhere the other half and I would love to go?
Initially and ironically, the very fact I'd signed up for the day's session made me more, rather than less, anxious in the run-up to the big day which involved flights to and from London.
It was the same when I'd gone on a Press trip to Thailand in the late Eighties.
I was fine(ish) until we took the internal flight to Phuket and lovely Judith Chalmers from Wish You Were Here? approached me to say how sorry she was I'd got a problem and could she help. At that point, I knew I couldn't get on the plane. My cover had been blown and I made it down to our beachside destination by train, then home with the help of tranquillisers and Gordon's gin.
But on arrival on a recent damp Saturday at the airport, I was prepared to try different techniques and give it a go. Alison, a reassuring, very professional presence, introduced the small group to the idea that we might re-train our imaginations which hitherto had been working unpaid overtime, making us see the ascent to 35,000 feet as suicide.
She would be helping us re-edit things, change the habitual groove of thought, as well as letting Capt Brady provide the impressive facts and figures demonstrating that stepping onto a modern plane operated by a large carrier is actually safer than getting behind the wheel of the family car and heading down the motorway.
Of course, to a true phobic, statistics tend to produce a harrumph or the 'What if?' line of questioning, used to prove that we are right and this activity really is jolly dangerous.
Sensibly, just before the session on facts, figures and engineering, we learnt some relaxation techniques based on the concept of mindfulness, borrowed from Buddhism. Then it was into the detail, provided by a charming man who notches up 250,000 air miles a year.
He gave us chapter and verse on aeroplane banking – something one of our group found frightening. Apparently, it's a wing shift from the horizontal of only around 25% and without it, the plane couldn't turn right towards the Isle of Man and home. He also sorted out the noises, with the 'pings', which we helpfully chorused, something to do with the old 'no smoking' announcement. The other sound is apparently related to gears.
And no, the engine diminuendo that you hear as the plane levels out isn't risky fuel-saving. Well, it is fuel economy, but not risky.
During a break, I asked Harry whether he'd ever been frightened on a plane. He hesitated briefly, didn't use the f-word but said yes, he'd been concerned when one engine had gone on him, with a bang, climbing to a couple of thousand feet out of Gatwick. "I had to work out what to do quickly, but we circled and landed again ok."
The point is, he and his nearly 200 passengers comfortably survived. Procedures were followed. It wasn't a headline. Reassuringly, pilots have to do six monthly sessions at a realistic simulator working out how they'd cope with real problems like the New York near-disaster when the gutsy pilot landed on the Hudson River.
I was at this point feeling the way I often do at an airport, quite worried but also slightly excited. One of the group went for a fag break and said he was planning his tactics.
During the course, participants reacted in different ways.
When we ran through Capt Brady's fact session, I was aware that my anxiety went up a bit, maybe not to cruising altitude but higher than normal, I became aware that one guy who really grilled our pilot was looking slightly green. But he said he was determined to conquer his fears, which were impeding his successful business career – he needs to travel across the Irish Sea once a week.
Why did he have problems? Like me, he hadn't had a really bad flight, like me, he'd decided at one point that he just didn't want to enter the flying sardine can again. Unlike me, this decision had stuck. You could see his thinking shifting under Alison's tutelage, but maybe he simply needed an extra session or to experience the normality of 21st century air travel. He said his brother, also fearful, had been cured by working within sight of the Aldergrove runways. Seeing the normality of endless take-offs and landings helped him resume flying.
But after queuing to get on the plane, after sitting down in the lovely leather seats, he had second thoughts. He made for the exit and missed our uneventful flight to Heathrow.
What happened next surprised me, and began a shift of the tectonic plates of my psyche.
As we discussed what had led to our fear, I remembered my grandfather, Dr Herbert Moss, an aeronautical engineer and therefore obviously an expert, telling me when I was six that he'd never trust a modern jet engine.
Ping! I realised that his remark and that initial flight to Entebbe had given me priority boarding into the fearful flyers' club.
But here was a chance to start the journey towards the fearless flyers' club that Alison runs.
Would it work? As the afternoon wore on, I felt more confident.
We were told to use the three-D technique – Dispute the old thinking, De-stress (by using the wonderful relaxation technique we'd learnt) and gain Distraction.
Mine is usually burying my nose in a newspaper or magazine or gulping down a short story (currently, the Russians). I have also been known to down a G&T or at least have one on standby.
Others had equivalent light bulb moments – one guy whose whole family mistrusted flying, was visibly relieved as he sensed he didn't have to follow that old thinking.
With a dash of CBT (cognitive behavioural therapy), some sophisticated positive or realistic thinking, you can start to unpick even decades of negative thinking. And bypass the bit of lizard brain that teaches you to regard every new experience as a 'fight or flight' situation. Alison's techniques are already ratcheting up successes and she had the idea for the course after helping a colleague who was plane phobic. Since then, he's happily flown on skiing holidays and attended a family wedding in America recently.
As the taxi driver I consulted on the way to the George Best Airport said laconically: "I've no problem with flying and nor did my father. He said it was like getting on a bus and the turbulence was just bumps in the road."
Funnily enough, as Harry told us, pilots do regard their routes as motorways and side roads through the ether. To my immense surprise and delight, I had a pleasant flight over with Alison. And as we chatted, she reinforced the new way of thinking. I also had a taped positive visualisation exercise in my bag.
The flight back solo on Monday morning was the real test. Did the phobia begin again? Well, I listened to the 'pings' and the odd (but routine) sounds. There was a delay before take-off from Heathrow on a wet day.
But ... it was all right.
While not a totally fearless flyer yet – and Alison Clarke doesn't promise instant nirvana – I think I'm en route. I looked out of the window quite a bit, admired the cloudscape, went to the loo (walking down the aisle had seemed too precarious before) and felt pretty much at ease.
My helpful distraction was two girls and their parents just behind: "No I won't paint your nails on the plane, Phoebe."
Aer Lingus' slogan is 'Great fare, great care' and it's good they care enough to have thought of the 30% of their passengers who are anxious as previously the only courses ran out of London were with BA and Virgin.
Come fly with me? Yeah, I just might.
So, how does it work ...?
Psychologist Alison Clarke writes:
Many competent and intelligent people suffer from fear of flying in varying degrees. Some fly in a state of great anxiety while others suffer long and arduous rail or car journeys. Others still miss important family events and opportunities to explore the world.
Often referred to as an irrational fear, there is nothing that feels more rational in the mind of the troubled person, especially when they start to think about travelling by air.
Yet, statistically, air travel remains one of the safest forms of transport. According to the American Aviation Safety Network, last year was the safest since 1945.
Comparisons between driving and flying point to how much safer it is to fly than to drive which explains why a pilot will tell you that the most risky part of their job is driving to the airport.
So if flying isn't the source of the problem, it must be something going on within the passenger. That's good news because it means the passenger has the power to alter his or her experience. Fear of flying has its origins in the exaggerated function of the human imagination and the human capacity to defend itself from real or imagined threats. Taken to extremes, these normal thinking processes become unhelpful.
The more these painful thoughts are rehearsed in the person's thinking, the more they wear a groove and become a habit of thought that is eventually an impediment to making free informed choices. The more often the thought is repeated, the more it appears real.
Overcoming fear of flying requires learning new information and unlearning old habits of thought. During the course, people learn the facts about flying and how to retrain their thinking to enable them to take to the skies with increased confidence.
Famous fearful flyers
• Agnetha of Abba – after flying through an electric storm on a short haul flight in the US in 1979, she refused to fly. Recently, the singer said she's overcome her nerves with the help of a therapist.
• Dennis Bergkamp was dubbed the "non-flying Dutchman" after he decided to stop flying following an engine cut out in the plane carrying him and teammates to the 1994 football World Cup in USA.
• Megan Fox, who resolves her aerophobia by always listening to Britney Spears music in the air. She explains: "I know it isn't my destiny to die listening to Britney Spears ..."
... and famous fearless flyers
• David Frost famously commuted to America in the 1970s when he was on the box on both sides of the pond, often taking the redeye to film his show Frost on America.
• Fergie, the Duchess of York, learnt to fly in the early 1990s so she'd understand what her then husband Prince Andrew, a helicopter pilot, was doing when he was at work.