The Federal Aviation Administration issued new rules for model aircraft and small drones June 18, reiterating that it is against the law for people to use them commercially.

Business people are increasingly using helicopterlike drones for a variety of purposes, including agricultural monitoring and real estate photography. People who do so are not hobbyists, the agency said.

The document issued on June 18 also says people may not use drones to deliver packages for a fee — even if people pay for the product but the shipping is free.

The FAA is still sorting out how to integrate commercial unmanned aircraft into U.S. airspace, working toward a congressionally mandated deadline of September 2015.

The movie industry is asking for special permission to use drones on closed sets.

A California spokeswoman for unmanned vehicle industry told a San Diego audience recently that, lacking guidance for the commercial use of drones, people will use them anyway. The Association for Unmanned Vehicle Systems International represents the industry.

Companies such as Berkeley-based 3D Robotics Inc., which has growing operations in Otay Mesa and Tijuana, want to sell businesses drone hardware and software. The company bills itself as “the hottest startup in San Diego.”

In a June 22 press release, the FAA complained of reckless use of unmanned model aircraft near airports and large crowds of people, and said it may take action against people who endanger the safety of the national airspace system.

Hobbyists may enjoy their hobby but they have to do it safely, the agency said.

The agency opened a 30-day public comment period for its rules on model aircraft.