I was a classic white-knuckle flier when I took up flying lessons 24 years ago, unable to board a commercial flight without severe anxiety. Now I take airline trips without a second thought and love to pilot small planes. But there are still times when I strap myself into my own plane with elevated blood pressure, wondering if it's really a good idea to make this flight. That happened earlier this month in Sturgis, S.D., when I took off much closer than I would have liked to a towering cumulus cloud that was rumbling thunder and spitting rain on my windshield.

This doesn't feel good, I thought. But there was no lightning, the wind was steady, I could see sunlight in all directions down the road, the local airport guru told me he had seen this stuff a million times before and that I should take the opportunity to get the heck out of there before it started hailing. If I had flown into a downdraft and smashed myself to bits on the runway, people would have said I was stupid to take off. Instead, within 30 seconds of going to full power and starting my takeoff, I was in the air, in the sun and leaving the cloud safely behind.

All of which is to say that small-plane pilots who want to do anything more ambitious than fly around the local airfield on perfect days often have to make complicated decisions for which there is rarely a perfect choice. Should I go or not? How bad is the weather? Can I handle this? Do I want to fly that far over water? What if the engine quits? Is it too windy to land where I'm going? Is this really as bad as it looks, or am I just being paranoid?

Out of an abundance of caution, I've canceled plenty of trips I later concluded I could have made with little or no problem. Being a small-plane pilot means having to tell your friends, who have trekked all the way out to the airport with you, that it's not such a hot idea to hop over to Ocean City after all, because there are some low clouds and possible thunderstorms sprouting over the Eastern Shore. It also means calling your goddaughter in Erie, Pa., and telling her you won't be there, as you had promised six times, for her seventh birthday. And listening to her cry while her father wonders why you got that stupid airplane, anyway.

I probably would have been a better pilot if I'd made some or even most of those trips, since the only way you improve is to push yourself into situations that stretch your skills. But the line between better skills and . . . well, sudden and violent death, is sometimes hard to discern. I've made a couple of flights that I probably should not have made. I survived. One friend who came along, however, will never leave the surface of the Earth with me again. He did not like the sensation of being inside a washing machine on spin cycle. I was exhilarated at using my instrument flying skills to handle an ugly little storm and getting us down safely. He walked away thinking he had just escaped death.

Like every other small-plane pilot I've talked to, I assume John Kennedy Jr. had thoughts like these when he loaded up his Piper Saratoga with his wife and sister-in-law Friday evening a week ago and took off for Martha's Vineyard. In most conditions this is a simple flight, even for pilots with little experience, and the sprawling World War II runways on that island and on nearby Nantucket are a snap to find and land on. Imagine how it feels to breeze into one of the islands in your own plane after an hour or two of flying, while everyone else has to endure a long, hot drive and a ferry ride, or a flight to Boston or Providence and a cramped connecting flight.

I'll tell you how it feels: magnificent.

Curving down out of the bright blue afternoon sky over the Atlantic after a smooth, 2 1/2-hour flight from Washington to glide onto the long southwest runway at Nantucket's oceanfront airport is the sort of thing that makes all the expense and hassle of maintaining a plane and my flying skills worthwhile.

That's the bright side.

For a sense of the dark side, imagine what might have been going through Kennedy's mind as he inched through New York's Friday evening traffic and arrived at a small New Jersey airport with daylight waning. Internal alarm bells should have been going off by then--inexperienced pilot, darkness coming on, a flight with an over-water leg into potentially hazy conditions on a nearly moonless night. But as much of the world knows by now, he and his wife had a wedding to get to, and he had promised to drop his sister-in-law off on the way. Pilot magazines constantly preach about the seductive dangers of get-there-itis. But it can be powerfully hard to resist. What's the plane for, after all?

The first rush of flight is exciting and reassuring. Takeoff is one of the easiest things to do in an airplane (go take a lesson and the instructor will probably let you do it yourself, right from the start), and it provokes an adrenaline surge that has never left me in more than 800 hours of flight. If you were dithering on the ground about leaving, the indecision usually evaporates in the air. Let's go. Let's do it.

New York City at night is a profusion of light: houses, streetlights, cars and the area's three huge airports, which look from the air like enormous, garishly lit pinball machines. Kennedy was a pilot who needed to rely on outside visual cues to fly--the horizon, lights on the ground, a shoreline, any horizontal line that would let him know that the airplane was straight and level. For the first 40 minutes or so, he probably had plenty, as he progressed around the city and flew up the Connecticut coast, where he could probably see light from houses, cars on Interstate 95 and even on boats on Long Island Sound.

But then, somewhere near Westerly, R.I., he turned out over 40 miles of dark ocean toward Martha's Vineyard, and the lights vanished. Suddenly, he probably found himself looking into a featureless and inky gauze, searching hard through the windshield for a horizon, a shoreline, boat lights--anything to give him the visual references he needed to tell up from down.

It is shockingly disconcerting to blunder into conditions like these, even in the daytime. Suddenly you have little idea where anything is or what the airplane is doing. Your body can lie to you: It will tell you that you're climbing when you're descending, that you're turning when you're straight and level, that you're straight and level when you're turning. What you must do instantly is shift your gaze exclusively to the instruments on the panel--chiefly to the artificial horizon, a small, gyroscopically driven ball that mimics the Earth and tells you what the airplane is doing: climbing, descending, turning right, turning left.

Instrument-rated pilots have had the exacting training it takes to do this and continue on with no trouble. And even non-instrument-rated pilots like Kennedy have minimal training designed to help them survive. For them, the procedure is straightforward: Go to your instruments, make a gentle, 180-degree turn and go back to where the visibility was better.

But it is one thing to practice this in daylight, with an instructor, wearing a visored device that limits your vision to the instrument panel. It is another thing entirely to do it at night, under pressure, for real. If things proceed badly, what can happen is that the plane will bank ever so slightly to one side, which will progress into a steeper bank, which will further steepen and tighten into the chillingly named "graveyard spiral"--all without the pilot being aware of how bad things are getting. When he finally notices his altimeter madly unwinding, the natural human reaction is to jerk back on the yoke to stop the descent, which, alas, is precisely the wrong thing to do. It stalls the plane, which tips into a spin and plummets toward earth with all the flight characteristics of a stone.

There is a little plaque that is particularly popular with pilots. It bears a photo of a biplane smashed into a tree, above which is this legend: "Aviation in itself is not inherently dangerous. But to an even greater degree than the sea, it is terribly unforgiving of any carelessness, incapacity or neglect."

I have this photo at home, above the table where I do my flight planning. I keep it there to remind myself never to get too cocky about my abilities or the sad and preventable mistakes of others. Some of my fellow pilots have sniffed that Kennedy never should have made the trip. Given the outcome, it's hard to argue. But we were all low-time pilots once, and we've probably all flirted with just such a flight. We didn't go, but the truth is that given a little bad luck, weather that turned out to be worse than it looked, and a judgment call that went the wrong way, that might have been almost any of us.

George Hager, who writes for The Post's Business section, is a private pilot with an instrument rating. He is part-owner of a single-engine Cessna 182 and has flown throughout much of the United States.