Why does the Part not move up While holding down a button?

Well, as you said, it's a Normal/Server script. But, UserInputService is exclusive to Local script only.

So, what's the solution?

Well, you can use RemoteEvents to contact between Server and Client. This is what you can do :

-- Local script [Keep it in StarterCharacterScripts or StarterGui]
local UIS = game:GetService("UserInputService")
local RS = game:GetService('ReplicatedStorage')
local RE = RS:WaitForChild("REMOTE_EVENT") -- Your Remote Event

UIS.InputBegan:Connect(function(InputObject) -- Input began
    if (InputObject.KeyCode == Enum.KeyCode.E) then
        print("Input Began")
        RE:FireServer() -- A command to contact with server using RemoteEvents
    end
end)

UIS.InputEnded:Connect(function(InputObject) -- Input ended
    if (InputObject.KeyCode == Enum.KeyCode.E) then
        RE:FireServer() 
        print("Input Ended")
    end
end)

-- Normal script [Keep it in ServerScriptService]
local RS = game:GetService('ReplicatedStorage')
local RE = RS:WaitForChild("REMOTE_EVENT")
local Drone = workspace.Drone -- An assumed location of your drone in workspace

local HoldingEkey = RS.HoldEKey -- Add a bool value in ReplicatedStorage and name it 'HoldEKey'

RE.OnServerEvent:Connect(function(player) -- 'player' is the one who fired to the server

	if HoldingEkey.Value then -- If the value was true
		HoldingEkey.Value = false -- Make it false
	else
		HoldingEkey.Value = true -- If value was false, make it true
	end

	 while HoldingEkey.Value do
            Drone.Position = Drone.Position + Vector3.new(0,0,-0.1,0) -- position
            print("should move")
            wait(0.1)   
        end
end)

Comment down if you want explanation of something!

Lemme know if it helps!