A direct flight is a flight in which the traveler make no other stops. The plane leaves from its point of origin and arrives at the travelers destination making no other stops. A connecting flight...
If you meant Greenville South Carolina its 57 minutes at a speed of 500 mph. That's the average speed of an airplane.
15 hours
china is huge... but you could calculate flight time and distance on your own with this tool: http://flighttime-calculator.com/
Beijing (BJS) to Portland, ME (PWM) Shortest Flight Duration * 16 hours 55 mins * Via Washington Dulles International Apt, Washington (IAD)