Unaccompanied minor needs to travel? Keep this in mind.

You’re not married to your kids’ mother or father anymore, but he or she wants to spend time with the children at the holidays. But distance is a barrier. Or your parents want to spend the holidays with their adorable grandchildren, and they live halfway across the country.

The scenarios go on and on, but they mean one thing: Either you are flying with your young children or you are sending them as unaccompanied minors. Often, because of the cost or the time or both, it’s the latter.

Keep in mind that you’ll incur a fee besides the cost of the ticket.

Each airline has its own fees and rules for unaccompanied minors, so check the policies before you buy a ticket. Despite the differences in charges and regulations, most have one thing in common: Children must be at least 5 years old to fly alone.

In most cases, children 5 to 7 can fly only on nonstop flights. Some airlines allow unaccompanied minors that age on direct flights, which are flights that have a stop but don’t involve a change of planes.

Some airlines won’t allow unaccompanied minors of any age on connecting flights (which, unfortunately for whoever is footing the bill, can be less expensive), and those that do won’t allow them on the last connecting flight of the day just in case something happens that would strand your small-fry flier.

The best approach is to send unaccompanied minors on morning flights, or midday flights at the latest. This allows ample time and options for getting from point A to point B in case of inclement weather or mechanical issues.

The airlines have mandatory fees for unaccompanied minors, but the upper age range varies. American, Southwest and United require the service for children up to 11; Alaska requires unaccompanied-minor service for children up to 12.

Delta, Frontier, Spirit, US Airways and Virgin America require the service for children 14 and younger. If you want a child who’s older than the mandatory age to be escorted, most airlines will be happy to assist — for a fee.

The fees vary by airline. Alaska charges $25 each way for nonstop flights and $50 each way for connecting flights. Dallas-based Southwest charges $50 each way. Most airlines, such as American, Delta, Spirit and US Airways, charge $100 each way.

Frontier charges $100 each way for the cheapest tickets, known as Basic Fares, and $50 each way for Classic Plus, Classic and Economy Fare tickets. Those fees will increase in March, with charges of $150 each way for Basic Fares and $100 each way for the other fares.

United charges $150 each way. Virgin America charges are based on distance, with a fee of $75 each way for flights of less than two hours, $100 each way for flights longer than two hours and $125 each way for flights to and from Mexico.

These fees are usually nonrefundable, so if you pay and then cancel the trip, you are out the money, never mind the change fee you will have to pay to rebook a ticket, assuming you bought a nonrefundable ticket (which about 80% of all tickets are).

Some airlines charge one fee for multiple kids from the same family, or extended family, who are flying on the same itinerary. On Southwest, you have to pay the fee for each child.

You can avoid having to use the service and paying the fee if the minors are traveling with a passenger who meets the airlines’ minimum companion age. On Southwest, the minimum age of the companion is 12; on Frontier, Spirit, US Airways and Virgin America, it’s 15. On American, the minimum companion age is 16, and on Delta and United, it’s 18.

When your child flies as an unaccompanied minor, you may need to present the child’s birth certificate, passport or other ID at check-in. You will fill out paperwork, and you’ll need to designate who will be picking up the child at the destination. You also will need to provide contact information for that person, and he or she will need to show government ID at pickup time.

You may escort the child to the gate by getting a pass. Many airlines require that you wait at the gate until the flight has boarded, but even if it’s not required, it’s a good idea to stay at the gate until the flight has taken off. You never know when a plane might have to return to the gate.

A note about smartphones: If your child is old enough to handle a phone — and it’s not a bad idea for him or her to have one — make sure your progeny understands that a phone battery will run down if there are too many rounds of Candy Crush Saga. To avoid that, entertain the notion of a separate electronic device for video games. Books, small toys and snacks can help keep children entertained during a flight.

The government has an online booklet with helpful tips for kids flying alone at https://www.lat.ms/17iaz6b. It includes this important bit of information: “Airlines try to do everything necessary to make your child’s trip safe and comfortable. However, you should understand that unaccompanied-minor services do not include constant supervision or entertainment during the flight.”

Preparing your child for a flight, thankfully, costs nothing and pays off in case of complications.

travel@latimes.com