With so many people flying today, problems are bound to occur – and with rising fees, fuel surcharges, restrictive luggage policies and excess charges, it’s no surprise that more than 90% of flyers don’t like flying. 

The experience is so bad, 32 million potential trips never took place in 2016, according to a survey by the U.S. Travel Association. People decided it was not worth the trouble.

To identify the 13 biggest air travel complaints of 2018, 24/7 Wall St. reviewed the travel complaints most frequently filed with the Department of Transportation (DOT). The data comes from the Air Travel Consumer Report, a monthly report by the DOT, which has tallied incidents through September 2018.

Safety complaints, which are handled by the Federal Aviation Administration, and security complaints, which are handled by the Transportation Security Administration, are not included.

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Global air travel has boomed from 310 million passengers carried in 1970 to 4 billion in 2017. Domestic and foreign airlines serving the United States carried a record 965 million passengers last year, an increase of 3.4% from the previous record high of 933.1 million in 2016. Problems are bound to occur with so many […]
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The U.S. airlines receiving the most reports of each complaint, and the total number of each complaint for foreign airlines, as well as the month in which the most of a given complaint were reported, also came from the Air Travel Consumer Report.

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13. Advertising
> Total number of complaints: 46
> Worst month: September
> Worst performing airline: Spirit Airlines
> Number of complaints with foreign airlines: 13

Advertising complaints refer to messages that are perceived by customers as unfair, misleading or offensive. They accounted for less than 1% of total complaints this year and last. The 72 foreign airlines included in the same report received significantly fewer advertising complaints -- a total of 13 between January and September 2018.

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12. Discrimination
> Total number of complaints: 68
> Worst month: July 2018
> Worst performing airline: American Airlines
> Number of complaints with foreign airlines: 11

Discrimination complaints include civil rights complaints by air travelers (other than disability). They can be based on race, national origin, or religion. Between U.S. and foreign air carriers, American Airlines had the most complaints based on race -- a total of 11, as many as all foreign airlines combined -- through September 2018.

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11. Oversales
> Total number of complaints: 334
> Worst month: August 2018
> Worst performing airline: American Airlines
> Number of complaints with foreign airlines: 126

Oversale complaints cover all bumping problems and whether the airline complied with DOT regulations for overbooking, which require that no one will be denied a seat until the crew asks for volunteers to give up their seats in exchange for compensation. About 3% of total air travel complaints with U.S. airlines are about oversales. Carriers, however, are getting better at limiting overbooking -- the number of such complaints for almost every month in 2018 was lower than the same month in 2017.

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10. Other
> Total number of complaints: 393
> Worst month: July 2018
> Worst performing airline: United Airlines
> Number of complaints with foreign airlines: 138

The "other" category includes complaints by frequent flyers, cargo problems, security, airport facilities, and claims for bodily injury. About half of all complaints are filed by frequent flyers, and the total number has increased since 2017. They complain the most about long security and boarding lines, boarding queues, delays, and long walks on arrival, according to a survey by Oliver Wyman, a global consulting firm.

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9. Misconnection
> Total number of complaints: 520
> Worst month: August 2018
> Worst performing airline: N/A
> Number of complaints with foreign airlines: N/A

Missed connections fall under the flight problems category. American Airlines had the most flight problems complaints of any U.S. carrier, with a total of 570. The biggest reason for missing connecting flights is airline delays, according to a study by Travelers United, a non-profit. Airlines are not obliged to guarantee their schedules; the DOT's advice is to plan a trip accordingly. There are no federal requirements for handling passengers who are delayed at the airport.

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8. Disability
> Total number of complaints: 620
> Worst month: August 2018
> Worst performing airline: American Airlines
> Number of complaints with foreign airlines: 124

This category includes civil rights complaints by air travelers with disabilities. The total number of complaints went down slightly between January and September 2018 compared to the same period in 2017 -- from 664 to 622. Airlines got fewer complaints from people with disabilities, but these represented a slightly higher percentage of total complaints -- from 5.8% in 2017 to 7.1% in 2018.

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7. Refunds
> Total number of complaints: 1,017
> Worst month: September 2018
> Worst performing airline: American Airlines
> Number of complaints with foreign airlines: 587

Complaints about refunds include problems in obtaining refunds for unused or lost tickets as well as fare adjustments. The overall number of such complaints, which include carriers and tour operators, has gone up slightly; but the number of refund complaints against U.S. airlines only has gone down. Unlike Europe, there is no specific law or regulation in the United States requiring airlines to refund passengers. The DOT determines whether compensation is warranted on an individual basis.

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6. Fares
> Total number of complaints: 1,046
> Worst month: March 2018
> Worst performing airline: United Airlines
> Number of complaints with foreign airlines: 486

Fare complaints include incorrect or incomplete information about fares, discounts, overcharges, and price increases. In addition to airlines, travel agents have also been the subject of a lot of fare complaints -- a total of 115 through September 2018, with most of them directed at Justfly and Cheapoair.

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5. Delays
> Total number of complaints: 1,215
> Worst month: August 2018
> Worst performing airline: N/A
> Number of complaints with foreign airlines: N/A

Delays fall under the flight problems category, which American Airlines tops. Overall, the number of delay complaints is down by about a quarter since 2017. Most delays occur because a previous flight with the same aircraft arrived late (due to non-extreme weather, problems with airport operations, or heavy traffic volume), causing further delays. and. Technically speaking, delays are down, but it does take longer to complete a flight because airlines are padding their schedules. They are saying it will take longer than anticipated to arrive at your destination, so it looks good when they actually get there "early."

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4. Customer Service
> Total number of complaints: 1,241
> Worst month: July 2018
> Worst performing airline: American Airlines
> Number of complaints with foreign airlines: 371

Customer service complaints include reporting rude or unhelpful employees, inadequate meals or cabin service, and bad treatment of delayed passengers. The DOT also accepts passenger complaints about the Transportation Security Administration (TSA), which no longer publishes claims data. There were close to 14,000 complaints against the TSA between January and September 2018, the majority about courtesy and damage to personal property.

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3. Reservations, Ticketing, Boarding
> Total number of complaints: 1,475
> Worst month: August 2018
> Worst performing airline: American Airlines
> Number of complaints with foreign airlines: 682

Representing about 10% of all travel complaints, these are claims against an airline or a travel agent for making mistakes in reservations and ticketing, as well as problems making reservations and getting tickets, and problems boarding the aircraft that don't involve oversales. The online booking sites with the most complaints between January and September 2018 were Justfly and Expedia.

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2. Cancellation
> Total number of complaints: 1,542
> Worst month: August 2018
> Worst performing airline: N/A
> Number of complaints with foreign airlines: N/A

Cancellations fall under the flight problems category, which American Airlines tops. Carriers appear to be getting better at not canceling flights; the number of complaints filed with the DOT was down by a third, from 2,242 between January and September 2017 to 1,542 in the same period in 2018.

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1. Baggage
> Total number of complaints: 2,131
> Worst month: August 2018
> Worst performing airline: American Airlines
> Number of complaints with foreign airlines: 1,207

Claims for lost, damaged or delayed baggage, charges for excess baggage, carry-on problems, and difficulties with airline claims procedures are the biggest category of air travel complaints. Baggage complaints represent nearly 13% of all complaints in 2018. The situation is not getting much better; roughly the same number of claims were filed in the January to September period in both 2017 and 2018. Data reported by the airlines show an increase -- 1.2 million baggage reports last year compared to almost 1.4 million so far in 2018 -- with the worst-performing airline being Southwest.

24/7 Wall Street is a USA TODAY content partner offering financial news and commentary. Its content is produced independently of USA TODAY.

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