ANA already controls more than half of the landing slots at the capital's downtown airport, and adding more would bolster its lead over local rival Japan Airlines Co. Intrepid, Airbus and ANA all declined to comment on the spat. Other planned Skymark sponsors include Sumitomo Mitsui Financial Group Inc and the Development Bank of Japan, which are set to take a combined 33.4 percent stake. (Reporting by Maki Shiraki; Writing by Tim Kelly; Editing by Kenneth Maxwell)