Are you as confused as these travelers about United’s upgrade system?

When Marco Lippman booked his United Airlines ticket for a flight from San Francisco to Frankfurt, Germany, he received a message that “four tickets were left at this price” that qualified for upgrades. But when he tried to upgrade his ticket, he found himself on a waitlist. And United’s website still contained a notation that upgraded tickets were available.

JustFly charged me $500 for seat assignments — after I paid for my tickets

When Anne Lederhos needed to purchase air tickets between Boston and Rapid City, S.D., she visited JustFly.com, made a reservation and paid $1,575 for tickets on American Airlines. But when she received her credit card bill, there was also a separate charge for $578, listed as “seat assignments.”

Having a complicated citizenship caused an expensive problem for this traveler

Leon Razzon is convinced that his daughter, Lora, should have been permitted to fly from Raleigh-Durham to Istanbul with only a U.S. Passport, which was about to expire, and a Turkish citizen card. American Airlines denies her boarding — and now he wants compensation.

Those four missing letters on your child’s airline ticket will cost you $2,000

Damon Terzaghi plans a trip to New Zealand to introduce his recently born child to his family. When making the reservations, he mistakenly uses his stepson’s nickname on one of the four tickets. Of course, it doesn’t match the name on his stepson’s passport.

Is a French air traffic control strike a valid reason to deny EU 261 compensation?

Tim Murphy booked flights on Expedia for himself, his wife and their four children for an Italian vacation. A strike by French air traffic controllers threw a wrench in their plans. Now he wants to know if his missed connections are fixable.

Venezuela is not safe for tourists. Can I get a refund on our tickets?

Jorge Taborda and his wife decide to take a trip with their children to Venezuela to visit extended family. But now that they’ve taken a closer look at the current economic and political situation there, they would like to cancel their tickets and receive a refund. Can they?

Airberlin won’t compensate you for “time and inconvenience,” but will they pay for your missing clothes?

When Timothy Korst’s Airberlin flight arrives in Paris without his baggage, he files a claim for his lost bags. But Airberlin will not offer as much compensation as he wants — including reimbursement for “time and inconvenience.” Is Korst out of luck?

My Aeroméxico ticket was wrong, and I don’t want to pay the change fee

Gail Creath didn’t confirm her Aeroméxico ticket was booked for the correct date, and the flight left without her. Although the airline was willing to reinstate her ticket for a fee, she didn’t like that option — we don’t recommend what she did next.

Delta delayed our flight and the stress almost made my wife miscarry our baby

Darren Johnson and his wife were forced to cut short their trip to St. Thomas in order to return to Salt Lake City to be with their daughter, who needed major surgery. On the way home, Johnson and his wife found themselves stuck in the Atlanta airport during the infamous Delta computer outage of August 2016.

Here’s why you should triple-check your reservations before you hit “confirm”

There’s an old saying that the devil is in the details. It’s especially relevant when you’re dealing with air travel. That’s because if you don’t pay careful attention to the details when making your reservations, there can be the devil to pay.

Yes, you should be informed of the cost of preselecting your seat — before you are charged

Robert Rosofsky books and pays for a round-trip flight, with one leg on Delta Air Lines and the return on Virgin Atlantic. When he goes to select seats for his return flight, he finds he’s being charged an additional $76. Can he use our contacts to obtain a refund?

I was bumped from my Spirit flight. Wasn’t I?

When Bob Fournier received an email from Spirit Airlines indicating that his flight had been rescheduled, he thought he had been bumped. From where he sat, he was facing the same circumstances as if he had been involuntarily denied boarding: Not only was he unable to fly home at the originally scheduled time, but he also would have to book a hotel room for a couple of extra nights, rent a car and miss a day of work.

Get smart. Sign up for the newsletter.