How to detect if a player is jumping and is pressing a key after they jump?

I'm trying to make this thing that when the player is jumping, they will be able to press space again to transform their character. Is there anything wrong with my script? the transform part is working, it's just when the player is jumping and is pressing the spacebar again.

if Humanoid.Jump == true then
game:GetService("UserInputService").InputBegan:connect(function(input)
if input.KeyCode == Enum.KeyCode.Space then
for _, child in pairs(script.Parent:GetChildren()) do
is_transformed = true
if child:IsA("UnionOperation") then
child.CanCollide = false
child.Transparency = 1
Animator.Parent = nil
Humanoid.HipHeight = 1
end
end
end
end)
end

Here should be a way to do this:

local InputEvent
local LandingEvent
Humanoid.Jumping:Connect(function()
	local didSecondSpace = false
		if InputEvent ~= nil then
		InputEvent:Disconnect()
		end
		if LandingEvent ~= nil then
		LandingEvent:Disconnect()
		end
	InputEvent = game:GetService("UserInputService").InputBegan:Connect(function(input);
		if input.KeyCode == Enum.KeyCode.Space and didSecondSpace == false then
			didSecondSpace = true
			InputEvent:Disconnect()
			LandingEvent:Disconnect()
			for _, child in pairs(script.Parent:GetChildren()) do
				is_transformed = true
				if child:IsA("UnionOperation") then
					child.CanCollide = false
					child.Transparency = 1
					Animator.Parent = nil
					Humanoid.HipHeight = 1
				end
			end

		end
	end)
	LandingEvent = Humanoid.StateChanged:Connect(function(old, new)
		if new == Enum.HumanoidStateType.Landed and didSecondSpace == false then
			InputEvent:Disconnect()
			LandingEvent:Disconnect()
		end
	end)

end

I just free-handed it, didn't test it. So uh, yeah.