NEW YORK, May 16 (UPI) -- A reported practice by U.S. airlines to reduce the amount of spare fuel on planes in a money-saving effort is causing concern among some pilots, a survey says.

More than 20 pilots who filed complaints in the past year with NASA's Aviation Safety Reporting System saw the probability of increased diverted flights. They said less fuel would mean planes can't circle as long over airports when a landing is delayed, USA Today reported Friday.

In one example, an airline captain reported his Miami-bound flight had to refuel in Fort Lauderdale, Fla., because rain showers delayed his scheduled landing. The report said several other pilots had similar stories.

Airlines say planes remain safe because they take off with the amount of fuel required by the Federal Aviation Administration, which calls for enough excess fuel to reach their destination or a diversion airport and still fly for an additional 45 minutes.

A report by Calvin Scovel, the U.S. Transportation Department inspector general, found no evidence that any planes landed with unsafe levels of fuel, USA Today said.