Traffic growth at British Airways and Iberia owner International Consolidated Airlines Group slowed down markedly in November as the increase in passengers and capacity both eased.The airline conglomerate, otherwise known as IAG, said traffic as measured by revenue passenger kilometres rose at an annual rate of 5.9% last month to 15,342m.This compared with the 10.3% year-on-year growth registered in October and an 8.5% improvement in September.The number of passengers carried totalled 5.74m in November, up 8.5% on last year, but down from the 6.90m carried in October (+10.3% on October 2013) and the 7,48m carried in September (+11% on September 2013).Meanwhile, group capacity as measured by available seat kilometres was 4.5% higher at 19,805m in November, easing from the 7.7% growth in October and 8.5% growth in September.The passenger load factor, which measures how full its planes are, was 77.5% in November, up 1.1 percentage points from the 76.4% registered last year.