Which airport?

If CDG, you can get some lovely views across the city including the Eiffel Tower from Montmartre. Gare du Nord has left luggage, roughly underneath the Eurostar security area on the far west of the station. You could head there, drop your bags, walk/bus/taxi it up the hill, have a breakfast with a great view, return to the station, grab bags and hop on the RER to CDG.