Production tooling is undamaged and most of the parts and materials "looks good" inside factories battered by severe winds and tornados in Wichita, Kansas, Spirit AeroSystems says.
The aerostructures supplier to several commercial, business and military aircraft manufacturers remains shut-down through 17 April.
Spirit AeroSystems and a nearby plant operated by Boeing Integrated Defense Systems fell in the path of a Category 3 tornado, with wind gusts up to 269km/h (167mi/h).
The storm ripped open the roofs and walls of several production buildings on Spirit AeroSystems' sprawling campus, but no workers were injured.
Two days later, the company now says it is starting to make "good progress" with its recovery plan. Power has been restored to two substations and natural gas lines are being reactivated in certain zones.
Most staff have been ordered to remain home, but more than 100 senior managers have come in to evaluate the situation and develop recovery plans, the company says.
"Obviously our short term delivery schedule has been impacted and we are working closely with our customers to continue to provide the products they need," the company says.
Large airframers, meanwhile, are waiting to know the extent of the damage before assessing the impact on production schedules. Spirit AeroSystems, for example, manufactures the fuselage of the 737, and the nose section of the 787 and major structural elements of the 747 and 777.
Boeing says its supplier management department is in "constant" communications with Spirit AeroSystems, but it is still to early to know if there will be a major impact.
"We are working closely with our customers to continue to provide the products they need," Spirit AeroSystems says.
Email service, however, remains down through at least the end of today. Spirit AeroSystems is communicating with employees and the public using Twitter as its primary channel.