It's rarely convenient to cancel or postpone your flight because of ear trouble. It is highly recommended, however, that you don't fly if you have an acute ear infection, a severe head cold, or sinusitis. Consult your physician regarding this. If you still decide to fly, here are some ways to keep your ears from popping.

Swallow frequently, yawn, or gently blow through your nose while pinching the nostrils shut,
to equalize pressure within your ears. (Don't do this if you have a head cold, as it will promote
an ear infection.)
If you have a mild head cold, use a nasal spray to keep the nasal passages open. Oral
decongestant medications are also effective.

Infants and young children tend to develop ear pain when traveling by plane, too. To prevent discomfort and ear infections in your children:

Have your infant suck on a pacifier or bottle during the takeoff and landing. (Nursing a baby
helps, too.)
Ask your doctor about giving children a mild decongestant and antihistamine 1 hour before
takeoff and 1 hour before landing.