The nation's airlines are reporting fewer delays, overbooked planes and lost suitcases. So why are passenger complaints up?
In the first six months of 2015, airline passengers on U.S.-based carriers filed 9,542 complaints with the U.S. Department of Transportation, a 20.3% increase over the same period in 2014, according to data released Tuesday.
Airline critics say the problem is that airline service has declined since a series of mergers has put control of 80% of domestic flights in the hands of four carriers: Southwest, United, American and Delta airlines.
"Service has continued to deteriorate at an accelerating rate," said Paul Hudson, president of flyersrights.org, a nonprofit passenger rights group. "Our complaint lines have shown the increase. It's also the fact that seats are getting smaller and passenger space is getting smaller."
Complaints over customer service rose to 1,121 in the first six months of the year, compared to 832 in the same period last year, a 35% increase, according to the Department of Transportation.
Complaints about airfares nearly tripled to 870 in the first six months of 2015 from 296 complaints in the same period in 2014, according to the federal agency.
Florida-based Spirit Airlines reported the highest complaint rate, 19.16 complaints for every 100,000 passengers.
Airlines for America, a trade organization that represents the nation's airlines, said the rate of complaints against its members remained nearly flat for the period.
"Flying remains a bargain, as evidenced by the record number of people traveling this summer," said Jean Medina, a spokeswoman for Airlines for America.
The good news for airlines is that the average on-time arrival rate in the first six months of the year was 77.65%, up from 74.15% last year.
The rate of mishandled bags dropped to 3.52 bags per 1,000 passengers in the first six months of the year, down from 3.84 bags last year.
The rate of passengers who were denied boarding because airlines overbooked their flights dropped to 0.82 per 10,000 passengers in the first six months of the year, down from 1.20 in the same period last year, according to the Department of Transportation.