Amazon.com has taken a 9.99% stake in Air Transport Services Group, the company from which it will be leasing freighter aircraft.Last week, Amazon said it had signed a deal with ATSG to lease 20 Boeing 767 widebody freighter aircraft to handle more of its own deliveries in the United States.As part of the agreement, Amazon has the right to buy up to 19.9% of ATSG`s stock over five years at $9.73 per share.Amazon took the stake in ATSG as of March 8, a day before the retailer publicly announced its deal with the company. ASTG shares closed at $14.56 on Friday.