Formula, milk and baby food
YVR: 'Formula is allowed for those travelling with infants, along with certain exemptions to the liquids and gels regulations.' The detail comes from CATSA: with an infant younger than two (0–24 months) you can bring baby food, milk, liquid formula, water, juice and other baby items over 100 ml; powders and granular materials such as inorganic baby formula are capped at 350 ml total; gel and ice packs are allowed if they are cooling those items; and breast milk over 100 ml is allowed whether or not your child is travelling with you, provided you present it to the screening officer before screening. On the US-bound side TSA's rule is the equivalent: formula, breast milk, toddler drinks and baby food over 3.4 oz are allowed, do not need to fit in a quart bag, count as medically necessary liquids and must be declared at the start of screening.