When flying with kids, the challenges often start to stack up even before the plane leaves the gate.

Figuring out the fare for your child is often the first hurdle. Many factors like age, airline and distance affect cost. Generally, infants under the age of 2 fly free domestically and to most of Canada, Mexico and the Caribbean if they are on their parent’s lap. But this comes with some safety risks, as you can’t share a seat belt with your child. On international flights, airlines will generally charge a 10 percent fee for holding children under 2 in your lap.

While most airlines require purchase of a full-price ticket for children between the ages of 2 and 11, some, like Southwest, offer discounted fares. Be sure to check with your airline before booking, as fares and policies vary.

Policies and fares regarding checked bags and carry-ons also may complicate your trip. Many airlines give items like strollers, diaper bags and child safety seats special designation, which allows parents to carry on or check one of each item in addition to their regular checked and carry-on baggage.

If bringing a child safety seat, be sure it falls within the Federal Aviation Administration’s (FAA) guidelines. Look for a notice on the seat declaring: “This restraint is certified for use in motor vehicles and aircraft.” Airlines will not accept any seat not certified for use on an aircraft by the FAA. Check with your carrier to verify its policies and requirements, such as size.

Airlines like American, United and many international carriers offer other travel solutions for parents, such as free bassinets, on long-haul and some short-haul flights. These baskets are designed for infants, generally under 12 months, to lie down in a secure environment during the duration of the flight. Typically, they will hook to the wall in front of bulkhead seating, but some business-class and first-class cabins may have special compartments or shelves built into seats or the cabin for these bassinets. Note that, for most airlines, in the event of turbulence or when the seat belt sign is on, babies must be removed from the bassinet and held in a parent’s lap.

Bassinet design varies by airline, and each comes with its own length and weight restrictions – making it a good idea to explore the options and solutions offered to parents beforehand. The number of bassinets per flight will also often be limited, so be sure to book early to reserve one.

Getting your child safely, securely and affordably aboard the airplane is only half of the travel journey for parents, as airport security and customs, for international travel, can also be tricky to navigate.

Your child may need some form of identification, depending on the flight destination and airline. While the Transportation Security Administration does not require an ID for those under 18 traveling domestically with an adult, some airlines may request it before offering discounted fares, to ensure a child’s age. On international flights, all passengers, regardless of age, must have a valid passport.

Children may also need additional documentation for international travel. Parents should be ready with a copy of their child’s birth certificate to prove relation and, if traveling solo with a child, a notarized letter from the other parent verifying their permission for the child to travel internationally is strongly recommended. For single parents, or in situations where such documentation is not available, Customs and Border Protection recommends having other relevant paperwork, such as a death certificate or court decision, at the ready.

When traveling with children, it is always a good idea to thoroughly do your research to avoid unnecessary surprises and hassle at the airport.