Flyer billed at length by hotel (4)
I believe the answer is:
This clue is a double definition.
'flyer billed at length' is the first definition.
(bird with a long bill)
'hotel' is the second definition.
(French hotel chain)
'by' acts as a link.
(Other definitions for ibis that I've seen before include "Wading bird sacred to the Egyptians" , "Flier" , "sacred creature of Egypt" , "Type of bird" , "Eastern" .)