The forward cabin door is closed. Everyone is sitting down with their seat belts fastened. Then comes the gentle nudge as the airliner is pushed back from its gate. Then the aircraft stops, and you have no choice but to wait some more. Thirty minutes after departing the gate, your patience all but shot, the airplane accelerates into the sky and you wonder why this whole process of getting from the gate to cruising altitude has to be so difficult and delay-prone? A solution for this problem is being tested right now at Charlotte-Douglas International Airport in North Carolina. Called ATD-2, short for Airspace Technology Demonstration-2, the three-year field demonstration of software solutions to better manage air traffic to and from Charlotte, with an emphasis on more efficiently handling aircraft movements between gate and runway.