Negotiators on a military spending bill are at odds with Congress' armed services committees over President Bush's plan for full-scale development of the Air Force's Advanced Tactical Fighter.

House and Senate bargainers were still working out final aspects of a $268 billion package for the fiscal year that began Oct. 1, with hopes of formally submitting the legislation Monday.Earlier in the process, negotiators from the congressional appropriations committees adopted several provisions that vastly differ from a separate defense authorization bill worked out last week by members of the Senate and House Armed Services committees.

In that bill, lawmakers agreed to Bush's fiscal 1991 budget request for full-scale development of the Advanced Tactical Fighter, the aircraft intended to replace the Air Force's F-15.

The administration sought $283 million for full-scale development and $763 million to complete the demonstration and validation phase of the prototype aircraft.