(FORTUNE Magazine) – The corporate jet, essentially a 1960s U.S. invention, has largely remained a trapping peculiar to American corporate culture ever since, with 50% to 75% of the market for such planes residing in North America. Looking for growth they don't see coming in the U.S., however, the jetmakers would dearly love to see the concept spread abroad, so both Gulfstream and Canadair are betting their futures on two big, new intercontinental jets: the G V, which will not replace the G IV but augment the Gulfstream line, and the Global Express, which will do the same for the Challenger. These will be larger-cabined planes, selling for between $30 million and $35 million, which are capable of traveling 6,500 nautical miles -- New York to Tokyo -- compared with 4,200 for today's G IV and 3,600 for today's Challenger. The G V is expected to be available for delivery in 1997, and the Global Express in 1998. The coming of the new aircraft is significant for two reasons: First, they represent the most serious effort yet to sell big jets to international corporations outside the U.S. Second, they mark the first genuine head-to-head competition for Gulfstream at the top of the market. ''We're convinced that there's a market for 500 to 850 of these planes,'' says Bryan Moss, president of Canadair's aggressive business aircraft division, a subsidiary of Montreal-based Bombardier Inc. Both Canadair and Gulfstream Aerospace, based in Savannah, point to the same trends as fueling the prospects for the new planes: increased international business travel; heightened interest in the Asia-Pacific region, particularly Southeast Asia; and the potential for business development in the difficult-to-get-around former Soviet-bloc countries. Traditionally, though, some of the best prospects just haven't bought into the concept of the corporate jet. Says Gulfstream executive vice president Bill Boisture: ''At this point, the corporate plane just hasn't cracked the Japanese culture. They fly JAL.''