While airports grow more congested and flight delays more common, dozens of airports have lost millions to local interests who are illegally diverting airport revenue to pay for everything from garbage dumps to special deals for rich developers.

In numerous reports, federal auditors have charged airport officials from Tampa to Los Angeles with leasing federal land to private interests at below-market value prices.

In addition, auditors criticized the Federal Aviation Administration (FAA) for its lax enforcement of laws to prevent such revenue diversion. The agency also did not attempt to determine whether leases of airport property would ultimately be profitable for the airports. The FAA's failure to ensure airports are as self-sustaining as possible, as the law requires, has cost the federal government millions of dollars.

From 1992 to 1996, auditors uncovered problems at 23 of 43 airports studied and concluded that more than $170 million had been lost or misused. They also said that more than $25 million would be lost annually until the problems are fixed.

Auditors urged the FAA to look harder at leases, but the agency acknowledges that it continues to use the same procedure.

Most of the audits attracted scant attention outside the aviation world. But reports on the Los Angeles International Airport and Tampa International Airport have generated headlines and congressional concern.

In one example, Tampa International Airport gave a bargain basement lease to a rich developer that will cost taxpayers $500 million over a period of many years.

Reacting to similar abuses of airport revenue, Congress directed the FAA in 1994 to clarify its position on revenue diversion.

In 1999, the FAA published its final policy statement on revenue diversion. The policy details prohibited uses of airport revenue and lists actions the FAA can take against violators, ranging from withholding grant money to suing for damages in federal court.

But the FAA has used none of these tactics to enforce its revenue diversion policy.

The FAA's failure to address this problem raises a larger question: If millions of dollars are being diverted at the handful of airports auditors have studied, what is the true magnitude of the problem nationally?

What is certain is that taxpayers have been bilked for millions and that the FAA's inaction has failed to fix the problem. Congress should withhold future funding to all airports that continue to divert federal taxpayer dollars.