London's Heathrow Airport, the GAO says, has spent $883 million on infrastructure improvements, almost as much as the $927 million 18 U.S. airports have spent.
The GAO says about 83 percent of those funds are being used to widen existing taxiways and runways, and in some cases relocate taxiways. In other cases, taxiways and bridges need to be reinforced to handle the plane's weight. Other infrastructure upgrades include changes at gates and terminals.
"Although these changes to airport infrastructure were driven by the introduction of the A-380," the report says, they "will also benefit current aircraft and other large aircraft that may be introduced." The GAO says airport operators also told them the cost of getting ready for the A-380 will likely be recaptured in the economic benefits of the new plane.
But, says the GAO in its 72-page report, "The airports also anticipate implementing some type of operating restrictions to safely accommodate the A-380. Specifically, all 18 U.S. airports we visited anticipated imposing some type of operating restrictions on the A-380 or on other aircraft that operate around the A-380."
The issue of how to handle the huge aircraft is also being studied by the Federal Aviation Administration, which may or may not impose its own operating restrictions sometime in the future.
One question the GAO report did not answer was what impact the A-380 would have on already strained airport capacity. The accounting arm of Congress said it was just too early to say.
Fourteen airlines have ordered 156 of the superjumbos. No U.S. passenger carrier has placed an order for the $300 million plane, which has faced severe production delays.