– It came from the sky.

One moment, Eileen Peskoff was enjoying a hot dog after running with the bulls at a Petersburg, Va., racetrack. Then she was on her back, knocked down when a 4-foot drone filming the event in August lost control and dove into the grandstands.

“You sign up for something called running the bulls, you think the only thing you’ll get hurt by is a 1,200-pound bull, not a drone,” Peskoff said.

Drones flown for a business purpose, like the one that left Peskoff and two friends with bruises, are prohibited in the U.S. That hasn’t stopped an invasion of flights far beyond the policing ability of the Federal Aviation Administration, which since 2007 hasn’t permitted commercial drones in the U.S. while it labors to write rules to allow them.

Drones have nonetheless been used to film scenes in the Martin Scorsese-directed movie “The Wolf of Wall Street” and sporting events for ESPN.

They’ve inspected oil field equipment, mapped agricultural land and photographed homes and neighborhoods for real estate marketing.

Some deny they knew rules

All such flights in the U.S. are outside the rules. While the FAA hasn’t ruled out granting commercial-use permits, it has so far allowed operations only in the Arctic.

Some operators plead ignorance of the rules. Some say their flying is legal under exemptions for hobbyists. Using drones is so lucrative for Hollywood that they’re flown knowing they’re illegal, said one operator.

The FAA is aware the number of flights is increasing and tells users to stop when it learns about them, it said in an e-mailed response to questions. The agency said it’s considering new guidance on what’s permitted.

For every time the FAA orders an operator to stand down — as it did after a Michigan florist did a test delivery by drone Feb. 8, and in January with Lakemaid Beer, which posted a video online proposing 12-pack deliveries to Minnesota ice fishermen — untold others fly below the radar, said Patrick Egan, a Sacramento, Calif.-based author and producer of an annual unmanned aircraft expo in San Francisco.

Small drones available on the Internet or at hobby stores for less than $1,000 — some equipped with high-definition cameras like those made by San Mateo, Calif.-based GoPro Inc. — are flooding the U.S. and being used by tens of thousands of people, Egan said.

The FBI opened an investigation on March 4 after pilots on an Alitalia Boeing 777 nearing New York’s John F. Kennedy International Airport spotted a multirotor copter that came within about 200 feet.

At least six other pilots have reported close calls since 2011 with what they believed were hobbyists’ or cinematographers’ unmanned aircraft, according to NASA’s Aviation Safety Reporting System.

Budgets, politics are factors

While the government needs to do more to control the growth in drones, it has been “swamped” by political crosscurrents and budget cuts that have made it difficult to craft rules, said Doug Davis, who ran the FAA’s unmanned aircraft office in the mid-2000s.

As airline pilot unions call for strict standards on the qualifications of drone operators, advocates including Egan say the standards should be eased.

“The FAA is going to have to step up the enforcement of people who use these things,” said Sean Cassidy, national safety coordinator for the Air Line Pilots Association.

The FAA conducted 17 enforcement actions for illegal drone use in the 13 months that ended in July 2013, according to agency data that doesn’t include informal steps like phone calls.

It has issued one fine, which is being contested.

The FAA, set up to enforce manned aviation, doesn’t have the resources to enforce existing rules on a new form of flying that isn’t tied to airports and requires so little training anyone can do it, Davis said.

“The reality is there is no way to patrol it,” Davis said. “There’s just no way.”