The industry's poor performance reflects rising passenger demand coupled with congestion in the skies and on tarmacs. Also, the Federal Aviation Administration is facing a growing number of air traffic controllers nearing retirement age.
President Bush has demanded action to avoid another summer of record delays, but there is little consensus among airlines, airport operators, Congress and the administration on what should be done.
The nation's 20 largest carriers reported an on-time arrival rate of 64.3 percent in December.
Customer complaints rose nearly 40 percent to 849 in December compared with a year earlier.