Data collected by the CAA shows that for October-December 2013 on-time performance at 10 monitored UK airports stood at 80 per cent, a percentage point higher than in the year-ago period. On-time performance is defined as the proportion of flights that arrive or depart early, or up to 15 minutes late. Average delay time was 12 minutes, which matched 2012. Charter flights showed the most improvement with a three percentage point increase and a four-minute average delay. Across the whole year performance matched 2012 with 80 per cent of flights on time. The CAA monitored 324,000 and 13,000 charter flights to obtain the data.