Does a 3 year old need id to board plane?

Yes, a 3-year-old typically needs some form of identification to board a plane, although the requirements can vary by airline and destination. Many airlines do not require children under 18 to have a government-issued ID for domestic flights, but they may need a birth certificate or other proof of age. For international flights, a passport is generally required. It's always best to check with the specific airline before traveling.