hahahahahaha ok, ok.

the stronger the headwind the longer the travel will be, simply because it goes against the aircraft which reduces the speed and makes time travel longer. plus add up the air-traffic on a certain area, the aircraft would be directed by the air traffic controllers to take certain routes/height to avoid collision in mid-air and if there are a lot of traffic on gourd (i.e take-off and landing) it could also add up the time.