A、 air traffic control
B、 unfavorable weather conditions
C、 aircraft late arrival
D、 traffic accident
A、 waiting for passengers
B、 operational problems
C、 badweather condition
D、 air traffic control
A、 boarding bridge
B、 the shuttle bus
C、 passenger ramp
D、 assigned seats
A、 seats
B、 the balance for the aircraft
C、 mechanical problem
D、 safetyvideo
A、 icing
B、 close door
C、 the completion of the de-icing procedure
D、 clear cabin