Yes, flight journey with an infant can be a bit difficult especially because of their smaller Eustachian tube which gets blocked due to changes in air pressure during the flight.This may cause ear pain in the infant who would be at discomfort and cry due to the same.
Next Steps
One way to reduce or avoid the pain is to feed the baby(breast feed or bottle feed, though breast feeding is better) while during the ascent and descent when pressure changes in the flight are maximum. Feeding helps to keep the Eustachian tube open.