Watching the planes

This task is about reading information from a bar graph.
Keri lives right under the flight path of planes taking off from a large airport.
One day she counted how many Air New Zealand and how many Jetstar planes took off.
She drew a bar graph, turned on its side, with the bars placed 'back-to-back', at hourly intervals. This graph is shown below.
 
Air New Zealand and Jetstar flights during the day

graph of flights times for air new zealand and jetstar aircraft

Question 1Change answer

a)  In what hour did no Jetstar planes take off at all? 

Question 1Change answer

b)   i) In what hour were the number of Air New Zealand and Jetstar takeoffs exactly the same? 
ii) How many planes in total took off in this hour? 

Question 2Change answer

c)  How many Air New Zealand planes took off in the afternoon? 

Question 3Change answer

d)  Over what two-hour period did exactly the same number of planes from each airline take off? 

Question 4Change answer

e)  Describe one thing in the pattern of takeoffs which is the same for both airlines.