The most significant movement in the Statement of Financial Position between December 31, 2017 and December 31, 2018 was the reduction in the net book value of Fixed Assets - Aircraft. The net book value decreased by $1.4 billion following the sale of 116 aircraft with a net book value of $6.1 billion and depreciation and impairment of $657.1 million, partially offset by new acquisitions totalling $5.3 billion. Of the 116 aircraft sold during the year, 72 were intercompany sales.