American Airlines, the world’s largest carrier, will add five to seven minutes to the time scheduled for each flight at its largest airports to reduce delays plaguing American travel.

The airline, a unit of Fort Worth, Texas-based AMR Corp., will begin operations earlier and fly later each day to avoid dropping any flights from its schedule, the senior vice president of global sales, David Cush, said.

“We are adding back some aircraft ground time to take some pressure off” and reduce delays, the chief executive officer of AMR, Gerard Arpey, said in New York, as the airline opened a new $1.3 billion terminal at John F. Kennedy International Airport.

American ranked 13th of 19 carriers in on-time arrivals for the year ending in June. Only 73% of American airline flights arrived on time in the first half of 2007, the worst rate since 1995, when the government began keeping comparable records.

The additional times will be added to “virtually all” flights from American’s largest hubs at Dallas-Fort Worth and Chicago, Mr. Cush said in an interview. Time also may be added to flights at other hubs, Mr. Arpey said.

AMR shares rose 80 cents, or 3.4%, to $24.16 at 4 p.m. in New York Stock Exchange composite trading. They have declined 20% this year.

Just 57.9% of American flights were on time in June, a month when Dallas-Fort Worth International Airport had thunderstorms on more than 20 days.

In addition to extending flight times, American will increase the time it allocates for planes to sit on the ground between flights, Mr. Cush said.

The airline is also studying whether it can add efficiency by keeping flight attendants on the same planes, rather than having them switch throughout the day. American earlier made such a change with its pilots.

“We recognize, and the industry recognizes, this is the operating environment we’re in for the next several years,” Mr. Cush said.