By Guy Taylor Heathrow reported its busiest ever December this year, driven by booming demand for transatlantic travel and a bumper Christmas. Some 6.6m passengers passed through the west-London hub last month. Of those, 1.6m involved trips across the pond, helping New York’s JFK airport clinch the top spot as the most popular destination for the year. The record month was also boosted by nearly 800 flights departing on Christmas day and carrying 142,000 passengers. December brought Heathrow’s total annual passenger numbers to 79m over 2023,a year which saw Europe’s busiest hub finally break p…