With air traffic down by 20% since the Sept. 11, 2001, terrorist attacks, and with some carriers using smaller jets, officials are hoping that delays at LAX will not climb significantly, despite losing one-fourth of its runways during the relocation.
"Of course there's going to be an impact," Shappi said. "During certain time frames there might be reportable delays, but we don't think we're going to get into any sort of gridlock scenario."
A reportable delay is defined as an arriving flight that is more than 15 minutes late. In the aggregate, on-time arrivals at LAX already have declined somewhat this year.
Surrounding communities also will be affected by the project, which will require aircraft to taxi greater distances and idle longer, temporarily increasing harmful emissions, according to environmental studies conducted for the runway project.
"When they start increasing the number of operations on those other three runways, then the people are going to be upset," said Roy Hefner, a Westchester resident who is on an airport committee that studies noise.
Airport officials and the main contractor that is reworking the southern runway complex, Tutor-Saliba Corp., have promised to reduce noise, emissions and dust by retrofitting construction equipment and continuously watering down the site. The city's airport agency also hired an independent company to monitor requirements to ease effects on the community.
With construction in full swing in a matter of days, air traffic controllers caution that mechanical problems or bad weather could throw off their best-laid plans.
"If there's an aircraft mishap, like someone's gear collapses on the runway, and now we're down to two runways," the FAA's Shappi said, "all bets are off."
The project aims to improve airport security and prepare the airport for a new generation of jumbo jets.
The airport historically has had among the nation's highest rates of runway incursions. On a typical day there, airplanes will cross active runways 900 times.
In 2009, the airport's 10,000-foot main north-south runway will be closed for six months for major reconstruction estimated at $7.5 million.