Introduction Globally, it is always believed that maintenance costs for most aircraft depend on the age of the aircraft. Nevertheless, Stephen Ruth, the new president and board chairman of North-South airlines quickly noted that from the historical perspective there has always been a significant difference between maintenance cost and age of the aircraft. This is the main reason why North-South airline president, Stephen Ruth on November 12, 2008, assigned Peg Young the task to research the issue. Peg Young is the vice president of North-South airlines operations and maintenance. The questions that Peg Young was to study on were;  1. Determining the average correlation between the average fleet age and the registered direct engine maintenance age.  2. Determine whether there was any relationship between the registered fleet age and the known direct engine maintenance age. Notable to mention is that Young was to report back to Ruth by providing responses accompanied by actual quantitative or graphical evidence. Peg answers The first initiative Peg took was to construct a detailed record containing the average age of both Northern and Southern B737-200 fleets. He did this with the help of his staff. The age was constructed quarterly for example; since the introduction of the plane to service. This was constructively done on each aircraft introduced and that was in service from late 1999 to early 2000. Additionally, the total average age of each fleet was thereafter determined. Peg mathematically arrived at the figure by multiplying the numbers of days by the total number of hours each aircraft had been flown. This was calculated per day. The value obtained presented the average age of each fleet. Furthermore, Peg also calculated the average age of specific aircraft in each fleet. He did this mathematically by dividing the total fleet hours flown by the registered exact numbers of airplanes in service at that time. Notable to mention is that Peg also determined the average utilization data for both northern and southeast fleets. This was done based on the aircraft that were flown on 30 th September 2008. Peg calculated the average utilization figure by recording the actual total fleet hours flown on that specific day. The data obtained were mathematically divided by the total number of days for all the aircraft’s present at that time and which were on active service. Results of the study The data Peg obtained thereafter revealed that the average utilization for South-East airlines was 8.3 hours on daily basis. In addition, Northern airlines also recorded an average utilization of 8.7 hours per day. However, it’s important to mention that the average fleet age was always calculated towards the end of the first quarter of the year together with the average cost for example; North-South Airline Data for Boeing 737-200 Jets. Year                                               Northern Airlines Data    Southeast Airlines Data Airframe Cost per Aircraft                         Engine Cost per Aircraft  Average Age (hours)      Airframe Cost per Aircraft  Engine Cost per Aircraft  Average Age (hours) 2001                                               $51.80