The Cybex Sirona S360 is FAA-approved for use on aircraft, but that approval covers only the seat itself—not installation or use in a car

The Cybex Sirona S360 (sometimes called the Cybex 360) has received approval from the Federal Aviation Administration to be used as a restraint device on commercial flights. This means the seat meets FAA safety standards for aircraft use and can be brought through security and installed in a plane seat during flight. However, FAA approval is separate from car safety testing, and the two do not overlap.

Many parents assume that FAA approval means a car seat is especially safe or that it meets higher standards than other seats. That is not how the approval works. The FAA tests whether a seat can be safely secured to an airplane seat and will protect a child during aircraft turbulence or an emergency. The National Highway Traffic Safety Administration (NHTSA) tests car seats for use in vehicles. A seat can be approved by one agency, both, or neither—and each approval tells you something different about what the seat is designed for.

Key Takeaways

  • FAA approval means the Cybex Sirona S360 meets aircraft safety standards and can be used on commercial flights, but it does not indicate how safe the seat is in a car.
  • The seat must still meet NHTSA standards to be sold and used legally in vehicles in the United States, which is a separate testing process.
  • If you plan to fly with your child, an FAA-approved seat can save you money because you do not have to rent a seat at the airport or purchase an extra ticket.
  • The Cybex Sirona S360 is designed to rotate and recline, features that are useful in a car but do not factor into FAA approval.

How FAA approval differs from car seat safety standards

The FAA tests car seats for aircraft use by checking whether they can be securely fastened to an airplane seat, whether they will stay in place during turbulence, and whether they protect a child in the specific conditions of flight. The test does not involve a car, a car's crash dynamics, or the speeds and forces involved in a vehicle collision.

NHTSA, the federal agency responsible for vehicle safety, tests car seats by crashing them into barriers at highway speeds and measuring the forces on a test dummy. The seat must prevent the dummy's head from moving too far forward, keep the dummy centered in the seat, and protect against side-impact crashes. These tests are much more severe than what an airplane seat experiences. A car seat that passes NHTSA standards has been tested for car crashes; a car seat that passes FAA standards has been tested for aircraft use.

The Cybex Sirona S360 meets both standards. It is approved by the FAA for aircraft and meets NHTSA standards for use in vehicles. You can use it safely in both places, but for different reasons.

Why parents choose FAA-approved car seats for travel

The main reason to choose an FAA-approved car seat is practical: if you fly with your child, you can bring the seat on the plane and use it during the flight instead of holding your child or using the airline's lap-child policy. This means your child has a dedicated seat with a harness, which many parents find safer and more comfortable than holding a child for hours.

Without an FAA-approved seat, you have three options on a flight: hold your child in your lap (which is legal but offers no restraint), purchase an extra ticket so your child has their own seat and you can use a regular car seat (expensive), or rent a car seat at the airport (limited availability and often uncomfortable). An FAA-approved seat lets you use the seat you already own, which saves money and gives you a familiar, properly-fitted restraint.

The Cybex Sirona S360 is also a convertible seat, meaning it can be used rear-facing for infants and toddlers and forward-facing for older children. This versatility, combined with FAA approval, makes it useful for families who travel frequently by air and want one seat that works for multiple stages of childhood.

How to use the Cybex Sirona S360 on an aircraft

If you bring the Cybex Sirona S360 on a flight, you will need to install it in your child's assigned seat using the airplane's seat belt. The seat belt threads through the belt path on the car seat, and you tighten it the same way you would in a car. The process takes a few minutes and does not require tools.

Before you fly, check with your airline about their specific policies. Most major U.S. airlines allow FAA-approved car seats on board, but some have restrictions on which seats they accept or how they must be installed. Call the airline ahead of time or check their website to confirm that the Cybex Sirona S360 is permitted and to learn where to sit (usually a window or middle seat, not an aisle seat, because the seat extends into the cabin space).

You will also need to remove the car seat from the airplane after landing and carry it with you. The seat cannot stay installed between flights, so if you have a connection, you will need to remove it, carry it to your next gate, and reinstall it if your child is on that flight too.

NHTSA standards and what they mean for car safety

The Cybex Sirona S360 meets NHTSA standards for use in vehicles, which means it has passed crash tests and is legal to use in a car. NHTSA does not "approve" individual seats the way the FAA does; instead, manufacturers test their seats and certify that they meet the federal motor vehicle safety standard for child restraints (FMVSS 213). If a seat meets this standard, it can be sold in the United States.

When you use the Cybex Sirona S360 in a car, you are relying on NHTSA testing, not FAA testing. The seat's ability to rotate, recline, and adjust is designed for car use and comfort, not for aircraft safety. These features do not affect whether the seat is safe in a vehicle—they are just conveniences that some parents find helpful.

To use the seat safely in a car, follow the manufacturer's instructions for installation, harness adjustment, and weight limits. The seat should be installed with the vehicle's seat belt or LATCH system (Lower Anchors and Tethers for Children), and your child should remain in the seat for every car trip until they outgrow it or reach the age and size limits set by your state's laws.

What to check before buying the Cybex Sirona S360

If you are considering the Cybex Sirona S360 because you plan to fly, make sure the seat fits your child's current size and age. The seat is designed for children from birth (in rear-facing mode) through approximately 65 pounds (in forward-facing mode), though exact limits depend on the child's height and weight. Check the manual for the specific ranges.

Also confirm that your car can accommodate the seat. The Cybex Sirona S360 is wider than some car seats because of its rotating base, so it may not fit well in all vehicles, especially if you have three children and need to fit three seats across a back bench. Test the fit in your vehicle before purchasing, or check the Cybex website for a list of compatible vehicles.

Finally, consider whether the FAA approval is actually useful for your family. If you fly once a year or less, renting a seat at the airport or purchasing an extra ticket might be simpler than managing an FAA-approved seat. If you fly several times a year, the convenience and cost savings of bringing your own seat make the higher price of an FAA-approved model more worthwhile.

Frequently Asked Questions

Does FAA approval mean the Cybex Sirona S360 is safer in a car than other car seats?

No. FAA approval and car safety are tested separately. The Cybex Sirona S360 meets the same NHTSA crash-test standards as other car seats sold in the United States. FAA approval only indicates that the seat is safe to use on an airplane. Choose a car seat based on NHTSA testing and fit in your vehicle, not on FAA approval.

Can I use the Cybex Sirona S360 on every flight?

Most major airlines allow it, but policies vary. Some airlines restrict which seats they accept or require advance notice. Contact your airline before your trip to confirm the seat is permitted and to learn where you can sit. You will also need to remove and reinstall the seat at each connection.

Is the Cybex Sirona S360 worth the extra cost if I only fly occasionally?

That depends on your budget and how often you fly. If you fly once a year or less, renting a seat at the airport or purchasing an extra ticket may be cheaper than paying more upfront for an FAA-approved seat. If you fly multiple times a year, the savings add up quickly.

What if my airline does not allow the Cybex Sirona S360?

Some airlines have restrictions on car seat models or dimensions. If your airline does not permit the Cybex Sirona S360, you can hold your child in your lap during the flight (legal for children under 2), purchase an extra seat and use a different car seat, or rent a seat at the airport if available.

Do I need to install the car seat differently on an airplane than in a car?

Yes. On an airplane, you use the airplane's seat belt to find the car seat, not the vehicle's seat belt or LATCH system. The seat belt threads through the belt path on the car seat. In a car, you use the vehicle's seat belt or LATCH anchors. Always follow the manufacturer's instructions for each setting.