Simple Fly Script With a pretty good ui

 UserInputService = :()
 RunService = :()
 Players = :()
 TweenService = :()

 player = Players.LocalPlayer
 character = player.Character  player.CharacterAdded:()
 humanoidRootPart = character:()

 flying = 
 flySpeed =  

 screenGui = .(, .CoreGui)
screenGui.ResetOnSpawn = 

 openButton = .(, screenGui)
openButton.Size = .(, , , )
openButton.Position = .(, , , )
openButton.Text = 
openButton.BackgroundColor3 = .(, , )
openButton.TextColor3 = .(, , )
openButton.Draggable = 
openButton.Active = 
openButton.AutoButtonColor = 

 mainFrame = .(, screenGui)
mainFrame.Size = .(, , , )
mainFrame.Position = .(, -, , -)
mainFrame.BackgroundColor3 = .(, , )
mainFrame.Visible = 
mainFrame.Draggable = 
mainFrame.Active = 

 title = .(, mainFrame)
title.Size = .(, , , )
title.Text = 
title.BackgroundColor3 = .(, , )
title.TextColor3 = .(, , )

title.Font = .Font.GothamBold
title.TextSize = 

 credit = .(, mainFrame)
credit.Size = .(, , , )
credit.Position = .(, , , -)
credit.Text = 
credit.BackgroundTransparency = 
credit.TextColor3 = .(, , )
credit.Font = .Font.GothamBold
credit.TextSize = 

 flyButton = .(, mainFrame)
flyButton.Size = .(, , , )
flyButton.Position = .(, -, , )
flyButton.Text = 
flyButton.BackgroundColor3 = .(, , )
flyButton.TextColor3 = .(, , )

 slider = .(, mainFrame)
slider.Size = .(, , , )
slider.Position = .(, -, , )
slider.Text =  .. flySpeed
slider.BackgroundColor3 = .(, , )
slider.TextColor3 = .(, , )

openButton.MouseButton1Click:(()
    mainFrame.Visible =  mainFrame.Visible
)

  ()
    flying =  flying
     flying 
         flying 
             moveDir = .(, , )
             cam = .CurrentCamera
            
             UserInputService:(.KeyCode.W) 
                moveDir = moveDir + cam.CFrame.LookVector
            
             UserInputService:(.KeyCode.S) 
                moveDir = moveDir - cam.CFrame.LookVector
            
             UserInputService:(.KeyCode.A) 
                moveDir = moveDir - cam.CFrame.RightVector
            
             UserInputService:(.KeyCode.D) 
                moveDir = moveDir + cam.CFrame.RightVector
            
             UserInputService:(.KeyCode.Space) 
                moveDir = moveDir + .(, , )
            
             UserInputService:(.KeyCode.LeftShift) 
                moveDir = moveDir - .(, , )
            
            
             moveDir.Magnitude >  
                moveDir = moveDir.Unit * flySpeed
            
            
            humanoidRootPart.Velocity = moveDir
            RunService.RenderStepped:()
        
    
        humanoidRootPart.Velocity = .(, , )
    


flyButton.MouseButton1Click:(toggleFly)

slider.MouseButton1Click:(()
    flySpeed = flySpeed + 
     flySpeed >  
        flySpeed = 
    
    slider.Text =  .. flySpeed
)

UserInputService.InputBegan:((input, processed)
     processed   
     input.KeyCode == .KeyCode.F 
        ()
    
)