Around the World in Eight Megabytes When Microsoft put the original Flight Simulator program onto the market, in the early 1980s, I tried it for a while and then gave up. I had thought it would be fun to 'take off' from Meigs Field, the airport on the Chicago lakefront where the simulator was programmed to start, and fly between the skyscrapers of the city toward whatever destination I chose. But the on- screen scenery turned out to be sketchy and uninteresting. Worse, I had no idea how to 'land' the plane, at Meigs or anywhere else, and the program was not much help in teaching me. After ten or twenty flights that ended mainly with nosedives into the lake or countryside, I decided I could have more fun in other ways. A dozen years later I became interested in learning to fly (and land) real airplanes, and I thought I should look at simulators again. There were now a range of programs, which were much more effective in teaching flying skills--or at least certain skills. They had also become a form. of entertainment and virtual adventure captivating enough to attract vast numbers of users worldwide. According to Guinness World Records 2001, Microsoft's Flight Simulator had sold a total of 21 million copies by June of 1999. Simulators' success is certainly deserved. Not many people fly real airplanes fewer than 650,000 Americans are licensed pilots. But a larger group probably would like to fly. And even people who have almost no interest in flying (surely everybody finds it a little bit exciting to pretend to zoom through the air) or who view computer games as inherently creepy would find it hard to ignore the best modem versions. On a big, high-resolution computer screen you can find yourself facing all amazingly exact rendition of a Learjet cockpit, flying low over the Grand Canyon at dawn, with flashes of lightning visible in the distance, as you listen to air-traffic controllers direct you to the Flagstaff airport. You can take off in a pontoon plane from a lagoon in Bali, fly over paddies on the terraced hillsides, and then head toward java's volcanic craters. You can approach Ayers Rock, in the center of Australia, and watch shadows move across it as the sun goes down. You can indulge in much of the visual romance of flying, without the time, expense, and training required to pilot a real plane. These riveting effects are the result of an intriguing de facto division of labor. The programs themselves are ail commercial products, from Microsoft and a number of small firms. But a wide variety of add-ons and improvements come from tens of thousands of hobbyists around the world, who spend countless hours polishing or improving some aspect of a program--and then post their work on the Internet for others to share. The flight-sim culture is a delightful reminder of a long-forgotten era, somewhere back in the 1990s, when people were excited about creating software for the new things it would let them do, not simply as a means of gaining market share. The flight-sim market resembles the rest of the software business mainly in that the most popular offering is from Microsoft. The current version of Microsoft's program is Flight Simulator 2000, or FS2000, which computer discounters offer for about $50. (A 'professional' version costs about $70. It includes more simulated airplanes and a larger number of places whose scenery is presented in extra-realistic detail.) With FS2000 and most other programs you can 'fly' from practically any point on earth to any other the differences among the programs lie mostly in the degree of scenic detail, plus certain aspects of the airplanes' look and performance. With all these programs you can also specify the weather conditions through which you'll pass on any particular trip: clouds, wind, turbulence, rain. The fanciest programs let you download the real-time weather for your route, from aviation sites on the