You must request this service prior to the day of your flight, as all food is made on the ground and loaded on the plane prior to take off. A terrific book, My First Plane Ride by Elizabeth Benjamin et al, provides youngsters the opportunity to explore the airport and plane with lift the flaps as well as a pop up airplane in the center of the book. This will free up your hands for wrangling children as you travel through the airport. A security toy, a puppet, a book, or some other item your children enjoys that is relatively small would be perfect. Provide one or two new items for your child.
New things are always exciting, and tend to occupy a child a bit longer than a more familiar toy.
You may want to save this surprise until your child grows impatient or weary and hard to manage. A new coloring book and crayons is a good choice for older children, and perhaps a puppet or exciting book for a baby. Extra clothing and diapers are a must. Pack enough for an entire day, as unexpected delays are common. Diapers tend to leak quickly while in the air, and should be changed more frequently than normal.