the most simple fly menu ever open source

local UserInputService = game:GetService("UserInputService")
local RunService = game:GetService("RunService")
local Players = game:GetService("Players")

local player = Players.LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local humanoid = character:WaitForChild("Humanoid")
local rootPart = character:WaitForChild("HumanoidRootPart")

-- Fly variables
local flying = false
local flySpeed = 50
local flyDirection = Vector3.new(0,0,0)
local bodyVelocity

-- Create ScreenGui
local screenGui = Instance.new("ScreenGui")
screenGui.Name = "FlyMenu"
screenGui.Parent = player:WaitForChild("PlayerGui")

-- Create main frame
local mainFrame = Instance.new("Frame")
mainFrame.Size = UDim2.new(0, 200, 0, 150)
mainFrame.Position = UDim2.new(0, 20, 0, 20)
mainFrame.BackgroundColor3 = Color3.fromRGB(30, 30, 30)
mainFrame.BorderSizePixel = 0
mainFrame.Parent = screenGui
mainFrame.Active = true
mainFrame.Draggable = true

-- Title
local title = Instance.new("TextLabel")
title.Size = UDim2.new(1, 0, 0, 30)
title.BackgroundColor3 = Color3.fromRGB(45, 45, 45)
title.BorderSizePixel = 0
title.Text = "Fly Menu"
title.TextColor3 = Color3.new(1,1,1)
title.Font = Enum.Font.SourceSansBold
title.TextSize = 20
title.Parent = mainFrame

-- Fly toggle button
local flyButton = Instance.new("TextButton")
flyButton.Size = UDim2.new(0, 160, 0, 40)
flyButton.Position = UDim2.new(0, 20, 0, 50)
flyButton.BackgroundColor3 = Color3.fromRGB(70, 70, 70)
flyButton.BorderSizePixel = 0
flyButton.Text = "Toggle Fly: OFF"
flyButton.TextColor3 = Color3.new(1,1,1)
flyButton.Font = Enum.Font.SourceSansBold
flyButton.TextSize = 18
flyButton.Parent = mainFrame

-- Speed slider label
local speedLabel = Instance.new("TextLabel")
speedLabel.Size = UDim2.new(0, 160, 0, 20)
speedLabel.Position = UDim2.new(0, 20, 0, 100)
speedLabel.BackgroundTransparency = 1
speedLabel.Text = "Fly Speed: 50"
speedLabel.TextColor3 = Color3.new(1,1,1)
speedLabel.Font = Enum.Font.SourceSans
speedLabel.TextSize = 16
speedLabel.TextXAlignment = Enum.TextXAlignment.Left
speedLabel.Parent = mainFrame

-- Speed slider
local speedSlider = Instance.new("TextButton")
speedSlider.Size = UDim2.new(0, 160, 0, 10)
speedSlider.Position = UDim2.new(0, 20, 0, 125)
speedSlider.BackgroundColor3 = Color3.fromRGB(100, 100, 100)
speedSlider.BorderSizePixel = 0
speedSlider.Text = ""
speedSlider.Parent = mainFrame

local sliderFill = Instance.new("Frame")
sliderFill.Size = UDim2.new(flySpeed/100, 0, 1, 0)
sliderFill.BackgroundColor3 = Color3.fromRGB(0, 170, 255)
sliderFill.BorderSizePixel = 0
sliderFill.Parent = speedSlider

-- Fly function
local function startFly()
    if flying then return end
    flying = true
    flyButton.Text = "Toggle Fly: ON"
    bodyVelocity = Instance.new("BodyVelocity")
    bodyVelocity.MaxForce = Vector3.new(1e5, 1e5, 1e5)
    bodyVelocity.Velocity = Vector3.new(0,0,0)
    bodyVelocity.Parent = rootPart
end

local function stopFly()
    if not flying then return end
    flying = false
    flyButton.Text = "Toggle Fly: OFF"
    if bodyVelocity then
        bodyVelocity:Destroy()
        bodyVelocity = nil
    end
end

flyButton.MouseButton1Click:Connect(function()
    if flying then
        stopFly()
    else
        startFly()
    end
end)

-- Update fly speed from slider
local dragging = false
speedSlider.InputBegan:Connect(function(input)
    if input.UserInputType == Enum.UserInputType.MouseButton1 then
        dragging = true
    end
end)

speedSlider.InputEnded:Connect(function(input)
    if input.UserInputType == Enum.UserInputType.MouseButton1 then
        dragging = false
    end
end)

speedSlider.InputChanged:Connect(function(input)
    if dragging and input.UserInputType == Enum.UserInputType.MouseMovement then
        local relativeX = math.clamp(input.Position.X - speedSlider.AbsolutePosition.X, 0, speedSlider.AbsoluteSize.X)
        local percent = relativeX / speedSlider.AbsoluteSize.X
        flySpeed = math.floor(percent * 100)
        if flySpeed < 1 then flySpeed = 1 end
        sliderFill.Size = UDim2.new(percent, 0, 1, 0)
        speedLabel.Text = "Fly Speed: "..flySpeed
    end
end)

-- Movement input tracking
local moveVector = Vector3.new(0,0,0)
local keysDown = {}

UserInputService.InputBegan:Connect(function(input, gameProcessed)
    if gameProcessed then return end
    if input.KeyCode == Enum.KeyCode.W then keysDown.W = true end
    if input.KeyCode == Enum.KeyCode.S then keysDown.S = true end
    if input.KeyCode == Enum.KeyCode.A then keysDown.A = true end
    if input.KeyCode == Enum.KeyCode.D then keysDown.D = true end
    if input.KeyCode == Enum.KeyCode.Space then keysDown.Space = true end
    if input.KeyCode == Enum.KeyCode.LeftControl then keysDown.Ctrl = true end
end)

UserInputService.InputEnded:Connect(function(input, gameProcessed)
    if input.KeyCode == Enum.KeyCode.W then keysDown.W = false end
    if input.KeyCode == Enum.KeyCode.S then keysDown.S = false end
    if input.KeyCode == Enum.KeyCode.A then keysDown.A = false end
    if input.KeyCode == Enum.KeyCode.D then keysDown.D = false end
    if input.KeyCode == Enum.KeyCode.Space then keysDown.Space = false end
    if input.KeyCode == Enum.KeyCode.LeftControl then keysDown.Ctrl = false end
end)

-- Update fly velocity every frame
RunService.RenderStepped:Connect(function()
    if flying and bodyVelocity then
        local camCFrame = workspace.CurrentCamera.CFrame
        local direction = Vector3.new(0,0,0)
        if keysDown.W then direction = direction + camCFrame.LookVector end
        if keysDown.S then direction = direction - camCFrame.LookVector end
        if keysDown.A then direction = direction - camCFrame.RightVector end
        if keysDown.D then direction = direction + camCFrame.RightVector end
        if keysDown.Space then direction = direction + Vector3.new(0,1,0) end
        if keysDown.Ctrl then direction = direction - Vector3.new(0,1,0) end

        if direction.Magnitude > 0 then
            direction = direction.Unit * flySpeed
        end

        bodyVelocity.Velocity = direction
    end
end)