Paying for that second seat might be worth it after all.

Lap Seats Aiplanes
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Being able to place an infant on your lap when flying is great for saving moeny, but a new study also indicates it can be dangerous.

Airlines typically allow parents to carry infants on their lap until the age of two, at which point they are required by federal regulations to have their own seat.

Research out of Cleveland's Rainbow Babies and Children's Hospital recently found that infants falling down from laps was the second most common cause of injury for them aboard flights.

Conducted in partnership with medical and travel safety provider MedAire, the study analyzed in-flight medical events for children up to age 18 across 80 major airlines on worldwide flights from 2009 t0 2014. Burns from hot drinks or soups were the most common cause of injuries for passengers under the age of two, followed by falling.

“Pediatric medical events on commercial airlines are relatively infrequent given the amount of passenger traffic, however unrestrained children, especially lap infants, are more likely to sustain an in-flight injury particularly during meal service or turbulence,” said the study's senior investigator, Alexandre Rotta, in a statement.

For parents flying with children, the Federal Aviation Administration recommends using a child restraint system. Parents and guardians should make sure that it contains the message, “This restraint is certified for use in motor vehicles and aircraft,” to be sure it can be used in-flight.

For injuries not specific to children under the age of two, the most common were burns, contusions, and lacerations.