ERP manages the business plan: orders, materials, inventory value, purchasing, costing, and financial transactions. MES manages production execution: dispatching work, capturing shop-floor activity, enforcing process steps, and preserving traceability. The boundary depends on plant configuration and integration quality.

No. In most aerospace environments, replacing MES is not a prerequisite for a connected operations platform and is often the higher-risk path. Brownfield plants usually get better results by integrating with the existing MES, ERP, PLM, and QMS stack, but success depends on interface quality, data readiness, validation effort, traceability requirements, and disciplined change control.