How can I keep my toddler's ears clear during take-offs and landings?

We will be taking our 19-month-old on her first flight in an aeroplane soon. How can I keep her ears clear during take-offs and landings?

Children of all ages suffer from negative pressure in the middle ear resulting from changes in atmospheric pressure. Infants should breast- or bottle-feed during take-off or landing. If your child drinks from a cup, try to get her to take a sip of something at those times. Sucking and swallowing helps relieve the pressure. As your child gets older, chewing gum or sucking on hard sweets, or yawning will all help equalise the pressure.