Sinus Problems & Flying, Not Pressure
 

My wife tends to get a sinus infection after flying. She doesn't have inner ear/sinus pressure problems. What would you recommend?

I'd recommend to ask your doctor...
I usually have some sort of nazal drops and use them every 2 hours or so.
AX

Ditto on AX's Dr recommendation.

In my experience, sinus infections often follow nasal congestion, so I try to keep clear even if it means saline mist, Afrin, or another decongestant, many of the same recommendations for inner ear pressure.

Perhaps it is the very dry air in the aircraft cabin that is causing her problem. Try drinking lots of water and using a saline nose spray before and during the flight.

Afrin and Halls Euchalyptus are a great combination
Also Sharper Image has this item you hang around your neck which act like a humidifier excellent for long trips.
Good luck