Clean lines, sweeping wings and wide oval windows: Gulfstream's G700 is among the most eye-catching aircraft at the Singapore Airshow, Asia's largest aviation and defence trade fair. Parked in a quieter corner of the tarmac, away from passenger jets and bulky military aircraft, it has drawn long queues of visitors waiting in the heat for a glimpse inside - a sign of the enduring interest in one of the world's leading private jet manufacturers. The lines move slowly. Sales conversations are