Imagine, then, a ride so fast it can make you black out and your nose bleed. A ride so wild, it plunges down faster than a peregrine falcon at an avian Santa Pod. A ride so hairy that it turns you up and down and sideways, imposing G-forces on your body so savage that no standard instrument can measure them accurately. This ride exists. It is called aerobatic flying. And week after week, more than 200 people in this country do this for fun.
Nick Buckingham, the chairman of the British Aerobatic Association, admits: "I can't get away from the fact that there is danger in it. Our planes are a bit like Formula One cars, but weigh less and go faster. But it's a lot more than that. It is about accurate geometry in the sky, and the real thrill is doing something arcanely difficult."
Chucking small aeroplanes around in the sky in manoeuvres straight out of schoolboy Airfix days seems more dangerous than being a 20-stone man at a cannibals' barbecue, but Buckingham insists it is actually very safe. "We have been running for 22 years and we haven't had a serious accident, let alone a fatality. We are neurotic about safety."
So what about all those hundreds of airshows that take place in the UK every year? He is quick to disassociate himself from formation flying and smoke trails. "I look aghast at what some people are doing at air shows. Their manoeuvres are often very dangerous and badly done. They would feel hopelessly lost it they tried to do what we do."
Now this sounds uncommonly like boasting, but it is not. Buckingham, from Slinford, West Sussex, is pretty good, but he has not yet joined the real acrobats, the elite fliers classed above advanced grade. They held their annual championships at Sywell, Northamptonshire, last weekend - and the winner was a 50-year-old housewife. It is the first time a woman has taken the title, but Diana Britten is no ordinary woman. She can put her Extra 260 aeroplane through manoeuvres that would have experienced pilots reaching for the sick bag. But she did not really want to take up flying at all.
It only happened because her husband lost his driving licence in 1980 and was determined not to be immobile. He decided to learn flying, and took Britten along. "He persuaded me, very much against my will, to have a go. That was it. I absolutely loved it."
She discovered aerobatics when undertaking some spinning exercises, then compulsory for a private pilot's licence. Spinning terrifies most pilots, but Britten enjoyed it so much that the instructor let her try loops and rolls, too.
Britten, from Chobham in Surrey, found an instructor who was a former member of the French aerobatics team, now the world's best. A year later, she entered her first competition, beating several of the men. Flying became an addiction, as bad as any glue-sniffer. "So I could practise and get the feel, I sawed a bit off the broom handle and sat on a large Indian cushion. The cleaning lady could not understand what had happened to the broom. But I used to do a lot of flying on my Indian cushion."
She moved quickly up the grades and into the area where many say: "That's enough". This is where a pilot learns that G can mean Gravity or Gee or Godhelpme. "A lot of people drop out then. But for me, it was even better. Anyway, there are things you can do when you are pulling lots of Gs, like pulling the stick back and bracing your stomach, closing your throat and panting really hard."
She became the first woman chosen for the British team in 1986, and helped by her husband, David, chairman of a public company, she bought her own plane. You don't get much for pounds 130,000: why, there's scarcely room for a bag of barley sugars. "You have to be strapped in so tightly that it hurts," Britten says. But the plane, like a racing car, has no optional extras to add weight. With a tuned 8,850cc engine, it can climb vertically or fly well below stalling speed. Just 21ft long with a 24.5ft wingspan, it makes you think of what Icarus might have produced with the right materials.
It is all designed to fly the geometric routines of aerobatics, described by Buckingham as "conceptualising square loops and diamond loops". It is also about spatial awareness. This is not always so simple when you have turned upside down and sideways three times in seconds and your instruments are still playing catch-up. The aim is perfect shapes, visible only to expert judges, and performed in an invisible box 1,000 metres square.
These magnificent men and women in their flying machines sound a fearless bunch, but it is only in their own world. Buckingham says: "I've raced cars but I think that's dangerous. It gives me palpitations." And Britten says: "Rollercoasters? You wouldn't get me on one of those. I'd be terrified."