The project execution plan sets out the strategy for managing the project, describes the policies, procedures, and priorities that will be adopted for the project.
While Project management Plan is the planning document, capturing the entire project end-to-end, covering all project phases, from initiation through planning, execution, and closure.
PMBOK® Guide 5th Edition vs PMBOK® Guide 6th Edition refers to The Project Management Plan is a document that describes how the project will be executed, monitored, and controlled, and closed.
Integrates and consolidates all ancillary management plans, baselines, and other information needed to manage the project.
The project needs to determine which components of the project management plan are needed "