I'm not sure if the evidence around cough and cold prevention is that robust. Washing your hands in alcohol gel between your 60th sore throat of the day seems like a good idea, but the reason I've not caught a cold yet this year probably has more to do with seasonal variations in the circulating strains, rarther than hand hygiene.
Sore,bunged up ears are probably a good reason not to fly, trouble is, where does one draw the line? In more virulent times, my ears have seemed to be bunged up all bloomin' winter.