Though airlines have different policies for children flying solo, they all make it a priority to keep them safe and comfortable.

This is the time of year when parents begin making plans for children to fly alone during the holidays.

I don’t have kids, but I empathize with those who do after recently flying our nieces, ages 14 and 17, from Ohio to Seattle. Airline fees for an unaccompanied minor can add up to $200 to the cost of a round-trip ticket, and there’s no bypassing the long lines at airport ticket counters, even if you’re not checking bags.

The trade-off, of course, is peace of mind for parents and sense of security for the kids. Our nieces received lots of special attention from the flight attendants. The pilot walked them off the plane where my husband met them at the gate.

Each airline handles the issue of children flying alone a little differently. Our nieces flew on Delta, which requires children 14 and younger to pay for “unaccompanied minor” service unless they are flying with someone 18 or older.

Southwest allows children 12 or older to fly as adults. Alaska and United set the age at 13, but give parents of older children the option of using the service if they want to pay for it.

Marianne Lindsey, of Alaska Airlines/Horizon Air, describes the service as an “insurance policy for parents.”

“We’re claiming responsibility for that child … Sometimes it goes great and sometimes there’s an issue … A flight is turned back or rerouted to another airport. The insurance is that the parent knows their child won’t be sent out into the Los Angeles airport on their own.”

Some pilots keep a few sets of wing pins in their pocket to hand out to young passengers, but “first and foremost, it’s all about ensuring the safety and security of the child,” says Lindsey.

The airline makes sure only a pre-authorized parent or other adult walks children through security to the gate area and picks them up at the other end. Flight attendants assist with connecting flights, help with carry-on items and safety instruction.

A few rules apply:

• Airlines don’t allow children younger than 5 to fly alone.

• Most charge just one fee for two or more children traveling together.

• Some require booking over the phone rather than online, and all require check-in at airport ticket counters. You’ll be asked to present a photo ID, fill out contact forms and get an escort pass to walk the child to the gate where you wait until the plane departs. Those picking up children must check in at the airport and follow similar procedures.

The biggest surprise for us was a Delta Air Lines requirement that its fee — now $100 each way, double what it was in April 2008 — be paid at the airport.

• Most airlines ban red-eye flights or the last connecting flight of the day and restrict the youngest to nonstop or direct flights requiring no change of planes.

• Food is usually not included beyond the usual soft drinks and pretzels, but there are exceptions. Delta offered our nieces a free lunch. United gives children a snack box.

Alaska accepts only credit cards for onboard purchases, but parents can sometimes buy vouchers that can be used like cash. Bottom line, says Lindsey, “if a child is hungry and they want something to eat, we’ll give them a free meal.”

Major airlines’ policies

Here are the major airlines’ policies. Some tweak the rules for international flights, so check with your airline. Updates and more details appear on their Web sites.

Alaska Airlines/Horizon Air (www.alaskair.com)

Fee is $75 each way for children ages 5-12 unless flying with someone 18 or older. Fee can be paid online or at the airport. Up to three checked bags allowed at no extra charge. No departures between 9 p.m. and 5 a.m. No connecting flights for children 5-7; connections OK for older children on Alaska/Horizon.

Southwest (www.southwest.com)

Fee is $25 each way for 5-to-11-year-olds unless traveling with someone 12 or older. Must be paid at the airport. No checked-bag fees. Only nonstop or direct flights.

Virgin America (www.virginamerica.com)

Fee is $75 each way for children 5-14 unless accompanied by someone 15 or older. Can be paid over the phone or at the airport. Nonstop flights only. Regular checked-bag fees apply ($20 per bag).

United (www.united.com)

Fee is $99 each way for 5-to-11-year-olds unless flying with someone 12 or older. Must be paid at airport. Regular checked-bag fees apply ($15 for first bag if paid online; $20 if paid at airport). Nonstop flights only for children ages 5-7; connecting flights on United or another airline permitted for those 8-11.

Delta/Northwest (www.delta.com and www.nwa.com)

Fee is $100 each way for children 5-14 unless traveling with an adult 18 or older. Must be paid at airport. Regular checked-bag fees apply ($15 for first bag if paid online; $20 if paid at airport). Nonstop or direct flights only for children 5-7. Connecting flights OK for older children if they stay on Delta or Northwest, and as of Nov. 1, KLM and Air France.

American (www.americanairlines.com)

Fee is $100 each way for those 5-14 unless flying with someone 15 or older. Must be paid at the airport. Normal checked-bag fees apply ($20 per bag). Nonstop or direct flights only for children 5-7; older children can take connecting flights on American but not other airlines.

Continental (www.continental.com)

Fee is $75 for nonstops and $100 for connecting flights each way for children 5-14 unless traveling with someone 18 or older. Payable online, through a travel agent or at the airport. Regular checked-bag fees apply ($15 for first bag if paid online, $20 at airport). Nonstops only for children ages 5-7; older children can fly on connecting flights operated by Continental.