Welcome in H.C.M.
I have gone through your queryregarding ear blockade in flight and followed by accumulation of fluid in ear. Though you are taking nasal spray
but your problem is still persisting .
I think you are having recurrent or chronic secretory otitis
media this may be manage as under-
1- Steam inhalation.
2- Anti histaminic & decongestant.
4- Antibiotic (preferably broad spectrum).
Probably above will help you but if above treatment failes than consult your ENT doctor for insertion of gromet in your ear drum.