Complex sentence: By 2005, the company had built its own two hangars and purchased its fourth Boeing B727-200 plane, and by the end of 2008 two Boeing B727-200 Super27 planes joined the fleet.
Split into simpler sentences: By 2005, the company had built its own two hangars and purchased its fourth Boeing B727-200 plane. By the end of 2008, two Boeing B727-200 Super27 planes joined the fleet.