By Andrea Shalal

WASHINGTON, Feb 18 (Reuters) - The U.S. Air Force is nearing completion of a study about U.S. air dominance in 2030 that will lay the groundwork for future purchases of a "family" of new combat weapons that could include a fighter jet, a top general said Thursday.

Lieutenant General Mike Holmes, deputy chief of staff of the Air Force for strategic plans and requirements, told reporters the study should be presented to top Air Force leaders next month. The next step would be a formal analysis of alternatives, which would pave the way for a new acquisition program in coming years, he said.

Lockheed Martin Corp, maker of the F-35 and F-22 fighter jets, Boeing Co, which builds the F/A-18E/F and F-15 fighter jets, and Northrop Grumman Corp, maker of unmanned planes and large parts of the F-35 and F/A-18 jets, are watching closely for clues about the future weapons program.

The Air Force is slated to declare an initial squadron of radar-evading, fifth-generation F-35 fighter jets ready for combat this August after 15 years of development work. But advances in radar technologies by Russia and China have prompted U.S. military leaders to start thinking about the next generation of combat planes beyond the F-35.

"It won't be just one airframe that comes out of it. It'll be a family of systems that helps us make sure we can guarantee the air superiority that the joint force depends on," Holmes told reporters after a speech hosted by the Air Force Association, a booster group for the service.

Holmes said the Air Force was also exploring potential electronic warfare capabilities as part of the effort.

Separately, Holmes said the Air Force planned to buy new helicopters to replace its aging fleet of 62 UH-1N helicopters built by Bell Helicopter, a unit of Textron Inc, which are used for security around Minuteman III intercontinental ballistic missile silos, and to provide VIP transports.

He said the Air Force's fiscal 2017 budget would start funding the effort, but decisions about how the acquisition would be structured have not yet been made.

He said one possibility would be to split the current mission into two, carving off the nuclear protection work, and potentially awarding a single supplier a sole-source contract.

Europe's Airbus, Bell Helicopter and Sikorsky Aircraft, a unit of Lockheed, have all expressed interest in building the new helicopters for the Air Force.

(Reporting by Andrea Shalal; Editing by Leslie Adler)