WASHINGTON (Reuters) - URS Federal Services Inc has been awarded an estimated $3.6 billion indefinite-delivery/indefinite-quantity U.S. defense contract for remotely piloted aircraft services, the Pentagon said on Thursday. Leidos, AASKI Technologies Inc and Textron unit AAI Corp will share in a $900 million firm-fixed-price contract for technical services and field support in support of Product Office Tactical Unmanned Aircraft Systems, the Pentagon said in a statement. Hologic Inc has been awarded a maximum $721 million firm-fixed-price, indefinite-delivery/indefinite-quantity contract for radiology systems, accessories and training, the statement said. 