Roblox script doesn't make part fly

Question

I have an issue with a Roblox script. This script is supposed make an object fly with a constant speed in the air but it doesn't work correctly. My programming knowledge about the Lua programming language is limited. When the Roblox game begins, the object immediately falls down. How can I fix this issue? Any help would be appreciated.

local All = script.Parent.Model:GetChildren()
for A = 1,#All do
    if All[A].Name ~= "Main" then
        local NewWeld = Instance.new("Weld")
        NewWeld.Name = "Weld"
        NewWeld.Part0,NewWeld.Part1 = All[A],script.Parent.Model.Main
        NewWeld.C0 = All[A].CFrame:inverse()
        NewWeld.C1 = script.Parent.Model.Main.CFrame:inverse()
        NewWeld.Parent = script.Parent.Model.Main
    end
end

local NewWeld = Instance.new("Motor6D")
NewWeld.Name = "Motor6D"
NewWeld.Part0,NewWeld.Part1 = script.Parent.Model.Main,script.Parent.Ref
NewWeld.C0 = script.Parent.Model.Main.CFrame:inverse()
NewWeld.C1 = script.Parent.Ref.CFrame:inverse()
NewWeld.Parent = script.Parent.Ref

while true do

    game:GetService("TweenService"):Create(NewWeld,TweenInfo.new(2,0),
    {C1 = script.Parent.Ref.CFrame:inverse()*CFrame.new(75,0,0)}):Play()
    wait(5)
    game:GetService("TweenService"):Create(NewWeld,TweenInfo.new(2,0),
    {C1 = script.Parent.Ref.CFrame:inverse()*CFrame.new(0,0,0)}):Play()
    wait(2)
end

Answer 1

It could be that script.Parent.Ref is unanchored. Try anchoring the object or use:

script.Parent.Ref.Anchored = true