Help on flying script?

Help and Feedback Scripting Support
#1

Why I cant move while flying I just stuck and cant move foward or backward ,can you help me and thanks
Capture
this is the local script :

local UIS = game:GetService("UserInputService")
local player = game.Players.LocalPlayer

local char = player.Character or player.CharacterAdded:Wait()

wait(1)

local IsFlying = false
local Torso = char.UpperTorso
local last = tick()

local function flight()
	local bv = Instance.new("BodyVelocity")
	bv.MaxForce = Vector3.new(math.huge,math.huge,math.huge)
	bv.Parent = Torso
	bv.Name = "FlightVelocity"
	bv.Velocity = Vector3.new(0,0,0)
end

UIS.InputBegan:Connect(function(input,gpe)
	if gpe then return end
	
	if input.KeyCode == Enum.KeyCode.Space then
		if (tick()-last) < 0.5 then
			IsFlying = not IsFlying
			if IsFlying then
				flight()
			else
				local bv = Torso:FindFirstChild("FlightVelocity")
				if bv then bv:Destroy() end
			end
		elseif IsFlying then
			local bv = Torso:FindFirstChild("FlightVelocity")
			if bv then bv.Velocity = Vector3.new(0,16,0) end
		end
		
		last = tick()
	end
	if input.KeyCode == Enum.KeyCode.LeftControl then
		local bv = Torso:FindFirstChild("FlightVelocity")
		if bv then bv.Velocity = Vector3.new(0,-16,0) end
	end
end)

UIS.InputEnded:Connect(function(input,gpe)
	if input.KeyCode == Enum.KeyCode.Space or input.KeyCode == Enum.KeyCode.LeftControl then
		local bv = Torso:FindFirstChild("FlightVelocity")
		if bv then bv.Velocity = Vector3.new(0,0,0) end
	end
end)