Atlas Air Worldwide Holdings AAWW, -1.05% and Boeing Co. BA, -1.55% announced Tuesday a deal to convert nine 767 wide-body passenger planes into converted freighters, up from an order of four planes previously-announced in July. In May, Atlas Air had announced a deal to provide air cargo services to Amazon.com Inc. AMZN, -1.27% including the operation of 20 767 freighters. Atlas Air's stock, which was still inactive in premarket trade, has gained 3.8% year to date, while the NYSE Arca Airline Index XAL, -1.23% has climbed 6.9% and the S&P 500 SPX, -1.24% has gained 5.9%.