Jeremy Jacobsohn guided his Piper Arrow down a runway at Lee Airport toward a kaleidoscope of fall color in the woods ahead. As the plane ascended, leaving suburban Edgewater behind, the houses became tiny dots and the Chesapeake Bay came slowly into view.

“This is the roller coaster part,” he said with a laugh.

Soon, Jacobsohn swooped south over the white-capped Chesapeake, then past the forested haven of Parker’s Creek in Calvert County toward Dominion’s liquefied natural gas plant under construction at Cove Point. He climbed to 2,000 feet for a panorama, then back down to 1,000 feet and east across the Bay for a closer look at the amber marshes hugging Deal and Hooper’s islands. Soon, he could see all of Ocean City out one window, then Chincoteague Bay and the long narrow buildings that hold the millions of chickens grown on the Delmarva Peninsula.

There’s nothing quite like seeing the Bay watershed from a small plane, both to appreciate its beauty and the coming threats. Environmental advocates have been using aerial photography to press pollution cases in courts, lobby for tougher laws and expose truths about disasters such as the hog waste from ruptured farm lagoons contaminating floodwaters in North Carolina this fall after Hurricane Matthew.

Those flights are about to become more frequent. Southwings, one of three national organizations of pilots who fly volunteer environmental missions, just opened an office in Annapolis in August. It is the first such group to set up in the Bay watershed. The effort is directed by Shannon Lyons, a longtime Bay policy analyst with a Ph.D. in marine policy. She has recruited seven pilots to take activists, journalists, scientists and policy makers into the air.

So far, Jacobsohn is the only pilot in Maryland; a software engineer by profession, he flies for fun every other Friday and has taken Southwings passengers on about a dozen missions so far. They have flown over coal mines to help the Sierra Club’s Beyond Coal campaign and over mountaintops removed by energy companies to look for evidence of erosion, loss of biodiversity and deforestation.

“The cases that Southwings was looking at really resonate with me due to my personal politics and my general guilt at being a consumer of all these things,” said Jacobsohn, who learned to fly two decades ago at the Dayton, OH, air force base located where Wilbur and Orville Wright perfected their pioneering flying machine. “I want to be sure we do what we can to mitigate the problem.”

Aerial photos have been a part of environmental litigation for decades, but advocates say they are becoming even more important because of privacy concerns and so-called “ag-gag” laws in effect in several states now that forbid citizens from going on a farm property to take photographs or videos. More than half of the states have enacted restrictions on drones and their use for photography, though not Maryland or Virginia — yet.

But while regulations are increasing on drones, no state appears to have a law outright banning aerial flights over farms and factories. (There is restricted airspace over much of Washington, DC, and about a dozen places with military bases and NASA operations for security reasons, as well as over Walt Disney World in Florida.) And as more pilots sign on to the environmental cause, more advocates are discovering the power of the view from the air.

“Almost everyone who walks through the door now has a photo,” said Jackie Guild, executive director of the Chesapeake Legal Alliance, which pairs nonprofit groups with attorneys willing to donate their time to environmental causes. Guild, a former litigator, said the photos help her figure out what kind of case the applicant might have. If she can see a discharge path, is it a Clean Water Act violation?

It was an aerial photo that triggered one of the Bay region’s most highly publicized — and ultimately unsuccessful — pollution lawsuits. In 2009, Assateague Coastkeeper Kathy Phillips flew over the Eastern Shore to look at chicken farms and photographed what she thought was a large pile of poultry manure, with water running from it to a nearby drainage ditch. Subsequent sampling downstream from the Berlin poultry farm owned by Alan and Kristin Hudson found high levels of E.coli and fecal coliform bacteria in the water that eventually flowed to the Pocomoke River. It was, however, a case of mistaken identity. It proved to be a pile of treated sewage sludge from Ocean City.

Phillips and the Waterkeeper Alliance sued the Hudsons and Perdue Farms anyway, alleging poultry manure from their houses was polluting nearby waters. But the federal judge in the case concluded that any pollution likely came from the Hudsons’ cows, which were not covered under the Clean Water Act, and that Perdue was not responsible. The case stoked tension between farmers and environmentalists that lingers years later.

But poultry farmer Virgil Shockley, a critic of the lawsuit, said that he doesn’t object to aerial photography. Most farmers, he said, don’t have anything to hide.

“If you’re doing what you should do, there shouldn’t be any conclusions to jump to,” said Shockley, a former county commissioner whose farm, like the Hudsons’, is in Worcester County. “If you do stupid things, then quite honestly, you’re stupid.”

The flights not only keep an eye on pollution, but they can inform policy. Recently, Jacobsohn took the Chesapeake Conservancy’s Joel Dunn and the Chesapeake Bay Commission’s Ann Swanson up with Lyons to see the Conowingo Dam. Swanson was surprised to discover swaths of undeveloped land near the dam, and wants to figure out how to protect it.

“It’s something you can see from the air,” she said, “and you can see it’s not out of reach.”

The “eye in the sky” often flies both lower and higher than it did a decade ago, and often without a pilot aboard. Some riverkeepers, like the Upper Potomac’s Brent Walls, have their own drones to survey localized pollution, such as a leaking stormwater pond or a sewage-treatment plant discharge. Walls, who has flown with Southwings several times, said the drone provides a closer view and can be available at times when weather or pilot unavailability prevents flying. Timing can be important in documenting a pollution problem, such as after a storm.

On the broader end of the spectrum is Skytruth, based in Shepherdstown, WVA. There, geologist John Amos and his team are watching and analyzing satellite imagery and picking up on radio frequencies to locate pollution and illegal activity, like fish poaching in the oceans. During the Deepwater Horizon oil spill, Amos and his colleagues reviewed satellite images of the disaster and determined the amount of oil spewing into the Gulf of Mexico was many times what BP was reporting. Government agencies followed up and concluded the spill was 60 times greater than wht BP had said.

Amos has also worked with Southwings to document spills and help pilots discern where to look for problems. Piloted flights can be expensive — about $100 an hour — but satellite images are free and available to the public. Working together, Amos said, environmental groups have an opportunity to combat pollution from billion-dollar industries and prove the need for stronger regulations.

Amos said the BP work is “an example of the power of observation. It’s your ability to be an eyewitness and look over your shoulder and call into question what you are being told by those in the know.”

He added: “Governments and industry do a better job when they know people are watching.”