Player jump in the air

first my godot version is 4.3
my problem is the player jump in the air here is my code
extends CharacterBody2D

@onready var ray = $RayCast2D

var inputs = {
‘ui_right’ : Vector2.RIGHT,
‘ui_left’ : Vector2.LEFT,

func _unhandled_input(event):
for dir in inputs.keys():
if event.is_action_pressed(dir):

func move(dir):
var vector_pos = inputs[dir] * 16
ray.target_position = vector_pos
if !ray.is_colliding():
position += vector_pos

var speed = 75.0

func _physics_process(delta):

velocity += Vector2.DOWN * 10.0 * delta

if Input.is_action_pressed("ui_up"):
	velocity = Vector2.UP * 5

There is no logic saying you are not allowed to jump while airborne. So add another conditional check too see if jumping is allowed before performing the jump.