When each "unit" you're selling is priced at $80 million, and there is a pent up worldwide demand, you can rack up impressive numbers in a hurry. Aerion, which is committed to developing and producing a supersonic business jet, left last month's EBACE show in Switzerland having sold the equivalent of a dozen-plus aircraft-a tally that boosted its order book by a cool $1 billion to a total of $4 billion. According to some heady arithmetic, that represents 50 airplanes. The Aerion supersonic business jet is expected to have a range that is roughly the same at both subsonic and supersonic speeds and should exceed 4,000 nautical miles. The aircraft will be designed to have a low sonic boom signature and cruise at up to Mach 1.1 with no boom at all. Its maximum cruise speed will be Mach 1.6. As staggering as the numbers are, the task ahead remains daunting, including not only the technical challenge of designing a Mach-busting bizjet at a profit, but also the political challenge of gaining regulatory approval. But for company vice chairman Brian Barents, so far, so good.