Complex sentence: During the summer of 2010, the airline purchased three Boeing 747-400BCF aircraft, at first the 747s were operated for the airline by Air Atlanta Icelandic before being registered in the United States in 2011.
Split into simpler sentences: During the summer of 2010, the airline purchased three Boeing 747-400BCF aircraft. These 747s were operated for the airline by Air Atlanta Icelandic initially, before being registered in the United States in 2011.