simple fly (open source)

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

local player = Players.LocalPlayer

local flying = false
local speed = 60
local bodyVelocity
local bodyGyro
local flyConnection

local gui = Instance.new("ScreenGui")
gui.Name = "FlyGui"
gui.ResetOnSpawn = false
gui.Parent = player:WaitForChild("PlayerGui")

local button = Instance.new("TextButton")
button.Size = UDim2.new(0, 140, 0, 50)
button.Position = UDim2.new(0, 20, 0.5, -25)
button.BackgroundColor3 = Color3.fromRGB(35, 35, 35)
button.TextColor3 = Color3.fromRGB(255, 255, 255)
button.TextSize = 20
button.Text = "Fly: OFF"
button.Active = true
button.Parent = gui

local corner = Instance.new("UICorner")
corner.CornerRadius = UDim.new(0, 10)
corner.Parent = button

local dragging = false
local dragStart
local startPosition

button.InputBegan:Connect(function(input)
	if input.UserInputType == Enum.UserInputType.MouseButton1
		or input.UserInputType == Enum.UserInputType.Touch then
		dragging = true
		dragStart = input.Position
		startPosition = button.Position
	end
end)

UserInputService.InputChanged:Connect(function(input)
	if not dragging then return end

	if input.UserInputType == Enum.UserInputType.MouseMovement
		or input.UserInputType == Enum.UserInputType.Touch then
		local delta = input.Position - dragStart

		button.Position = UDim2.new(
			startPosition.X.Scale,
			startPosition.X.Offset + delta.X,
			startPosition.Y.Scale,
			startPosition.Y.Offset + delta.Y
		)
	end
end)

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

local function stopFlying()
	flying = false
	button.Text = "Fly: OFF"
	button.BackgroundColor3 = Color3.fromRGB(35, 35, 35)

	if flyConnection then
		flyConnection:Disconnect()
		flyConnection = nil
	end

	if bodyVelocity then
		bodyVelocity:Destroy()
		bodyVelocity = nil
	end

	if bodyGyro then
		bodyGyro:Destroy()
		bodyGyro = nil
	end
end

local function startFlying()
	local character = player.Character
	if not character then return end

	local root = character:FindFirstChild("HumanoidRootPart")
	if not root then return end

	flying = true
	button.Text = "Fly: ON"
	button.BackgroundColor3 = Color3.fromRGB(0, 170, 85)

	bodyVelocity = Instance.new("BodyVelocity")
	bodyVelocity.MaxForce = Vector3.new(math.huge, math.huge, math.huge)
	bodyVelocity.Parent = root

	bodyGyro = Instance.new("BodyGyro")
	bodyGyro.MaxTorque = Vector3.new(math.huge, math.huge, math.huge)
	bodyGyro.P = 9000
	bodyGyro.Parent = root

	flyConnection = RunService.RenderStepped:Connect(function()
		if not flying or not root.Parent then
			stopFlying()
			return
		end

		local camera = workspace.CurrentCamera
		local direction = Vector3.zero

		if UserInputService:IsKeyDown(Enum.KeyCode.W) then
			direction += camera.CFrame.LookVector
		end

		if UserInputService:IsKeyDown(Enum.KeyCode.S) then
			direction -= camera.CFrame.LookVector
		end

		if UserInputService:IsKeyDown(Enum.KeyCode.A) then
			direction -= camera.CFrame.RightVector
		end

		if UserInputService:IsKeyDown(Enum.KeyCode.D) then
			direction += camera.CFrame.RightVector
		end

		if UserInputService:IsKeyDown(Enum.KeyCode.Space) then
			direction += Vector3.yAxis
		end

		if UserInputService:IsKeyDown(Enum.KeyCode.LeftShift) then
			direction -= Vector3.yAxis
		end

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

		bodyVelocity.Velocity = direction
		bodyGyro.CFrame = camera.CFrame
	end)
end

local function toggleFly()
	if flying then
		stopFlying()
	else
		startFlying()
	end
end

UserInputService.InputBegan:Connect(function(input, gameProcessed)
	if gameProcessed then return end

	if input.KeyCode == Enum.KeyCode.F then
		toggleFly()
	end
end)

button.MouseButton1Click:Connect(toggleFly)

player.CharacterAdded:Connect(function()
	stopFlying()
end)