1- As for wudhu, you can always use the lavatory in the plane and make a quick wudhu inside. If water is not accessible, then in your hand bag carry several torbahs and so tayammum on them.
2- As for praying, if you can ask for permission and find a corner to pray then do that. If there’s nowhere to stand and pray then pray in your seat towards Mecca. If you cannot, then towards any direction you can (facing the front of the plane).