WHY DOES NASA DO FLIGHT RESEARCH BASED ON A STATIONARY, NON-ROTATING FLAT EARTH?

We have come across some documents, official NASA research documents, comfirming that they do flight research based on a 'flat, non-rotating earth.' And this is AFTER they supposedly landed on the moon. Why? Why even take a flat, stationary earth into consideration when they supposedly KNOW that the earth is a spinning globe? Why spend money and time researching flight data based on a stationary flat earth, if there is no such thing? This makes no sense. Unless NASA has been lying to us all along! Take a look at the following documents. I have the documents downloadable from my website and also the original source location of the documents.

Derivation and Definition of a Linear Aircraft Model - "This report details the development of the linear model of a rigid aircraft of constant mass, flying over a flat, nonrotating earth." PDF - Original source

Stability and Control Estimation Flight Test Results for the SR-71 Aircraft - "These equations assume a rigid vehicle and a flat, nonrotating Earth." PDF - Original source

Investigation of Aircraft Landing in Variable Wind Fields - "The aircraft trajectory model employed in this study was derived based on the following assumptions: a) The earth is flat and non-rotating." PDF - Original source

A Mathematical Model of the CH-53 Helicopter - "The helicopter equations of motion are given in body axes with rerpect to a flat, nonrotating Earth." PDF - Original source

Flight Testing a V/STOL Aircraft to Identify a Full-Envelope Aerodynamic Model - "For aircraft problems, the state and measurement models together represent the kinematics of a rigid body for describing motion over a flat, nonrotating Earth." PDF - Original source

CALCULATION OF WIND COMPENSATION FOR LAUNCHING OF UNGUIDED ROCKETS - "In addition t o the above requirements, this simulation assumes avehicle with six degrees of freedom and aerodynamic symmetry in roll and the missile position in space is computed relative to a flat nonrotating earth." PDF - Original source

Trajectory Prediction of Spin-Stabilized Projectiles With a Steady Liquid Payload - "These equations assume a flat Earth." PDF - Original source

As I said above, why would you waste money and time doing research based on a flat stationary earth if you KNEW that the earth was a spinning globe? Makes you think doesn't it? NASA is all about deception!