A Few Suggestions

• If child in under one year old, make sure you travel with a pacifier or bottle to ensure that baby's ears don't pop when the plane takes off or lands.
• Bring more than enough diapers and wipes.
• Travel during bedtimes or nap times.
• Check the weather a few days before you travel to ensure that you are packed appropriate clothing. 
• If you are traveling by plane, make sure you inform the airline that you are traveling with a baby or toddler. When you check in, remind them about the baby and/or toddler to ensure you have boarding pass for him/her or them. 
• When traveling by plane, arrive earlier than recommended as you may need to wait in line to get a boarding pass for child and check in the stroller.
• Bring a blanket or a comfort item for child, I found this very helpful with my son.
• Bring formula for baby and snacks and beverages including milk for toddler. Most airlines will provide a beverage for toddler but its best to be prepared with your own beverages.
• When they are infants and babies, driving or flying in the plane is mostly about comforting the baby but when they are toddlers it is about comforting the baby but also entertaining the baby, so bring toys, play games in the plane, bring magazines or books, coloring sheets, etc.
• Have a passport for baby or toddler if you plan to leave the United States. They last up to five years.
• If you are traveling overseas, you have to pay 10% of an adult plane ticket for a lap seat. Make sure you book the lap seat at the same time you book adult seat. If you wait to the last minute you will be paying 10% of a last minute plane ticket.
• If you are traveling to a city you are not familiar with, it's best to book at least a 3-star hotel to ensure hotel amenities such as restaurants, shops, portable cribs, refrigerator, babysitters, etc.