1 Frankfurt Intl Airport (Frankfurt, Germany) 2  Right now, 120 airlines operate out of Frankfurt Intl Airport. 3  Frankfurt Intl Airport offers nonstop flights to 296 cities.  Every week, at least 4,564 domestic flights and 16,296 international flights depart from Frankfurt Intl Airport.
Keep your child who has outgrown his forward-facing car seat in a belt-positioning booster seat until they are big enough to fit in regular seat belts. Keep in mind that, according to the AAP, this is usually not until a child has 'reached 4 feet 9 inches in height and are between 8 and 12 years of age.'.
While it is not recommended to put a 3 year old in a booster seat (using the lap/shoulder seat belt in lieu of the five-point harness), it is not against the law. The law requires a child to be in a child restraint up to age 8, whether that is a booster seat or a five-point-harness car seat.