In 1936 the Short Calcutta (3-engine, open cockpit) and Kent (4-engine, fully enclosed) Flying Boats overflew Luxor southbound but nightstopped northbound, so there must have been a decent (for the time) hotel there.
http://www.timetableimages.com/ttima...f/iaw36f-2.jpg
The Short Empire Flying Boats had come along by 1938 and routed through Luxor both ways in 1938 :
http://www.timetableimages.com/ttima...f/iaw38f-2.jpg
By1939 Luxor was being overflown altogether and the Boat routed directly from Cairo to Wadi Halfa
Imperial Airways
The significant Imperial Airways point in Egypt was not Luxor or Cairo, but Alexandria, junction of the routes from Britain to Africa and to Asia, a mail sorting, overnighting and crew change point, also for the (few of course) connecting passengers proceeding from Africa to Asia).