American expected to cancel up to 2 percent of its total flights through the end of October because of a dispute with a pilots union.
The percentage of American flights arriving late has ballooned. On Sunday, Monday and Tuesday, fewer than half its flights arrived on time, according to flight-tracking service FlightStats.com.
At midday Thursday, 62 percent of American flights were on time, compared with at least 90 percent at United, Delta and US Airways, FlightStats' figures showed.
Executives with the company reportedly believe pilots are intentionally calling in sick and crews are slowing operations with overloads of maintenance reports. The pilots union disputes this.
Up to 2 percent of American Airlines flights were expected to be canceled through the end of October. The airline canceled 300 flights this week, and that was expected to increase. The canceled flights represent 1.25 percent of its schedule. On Sunday and Monday, more than 5 percent of its flights were canceled.
American Airlines is trying to cut $1 billion in annual labor costs. American and its parent company AMR Corp. filed for bankruptcy in November.
The airline has a history of poor relations with unions. Flight attendants and pilots went on strikes in the 1990s. In 2003 workers took pay cuts to keep the company out of bankruptcy, then were enraged when hundreds of management employees received bonuses that for a few topped $1 million.
Last September, a federal judge ordered the union for US Airways pilots to stop disrupting the airline by making sure flights were late. In 2008, a judge determined that United Airlines pilots carried out illegal sickouts and slowdowns and ordered them to stop.
American's pilot union was fined $45 million after a 1999 sickout over bringing in pilots from a low-cost airline that AMR bought. AMR and the union reached a settlement that reduced the union's loss.
American Airlines announced Friday it would not lay off flight attendants. Flight attendants in the union took early payouts of $40,000 each to reduce the chance of furloughs; 2,025 signed up for those severance payments. Their departures were expected to be staggered over the next year. American expects to begin recruiting new attendants in 2013.
The Associated Press contributed to this report.