Rob Sherman, who died over the weekend in a crash of his small plane in Marengo, operated a business helping people build aircraft from kits.

But the 63-year-old was better known as a colorful political activist and Green Party candidate — some might say gadfly — who called journalists and introduced himself as “Rob Sherman, your favorite atheist.”

At one time, he had license plates that spelled out ATHEIST.

Though he came in for derision as a self-promoter, he challenged the use of government-sponsored Christmas creches and displays and anything he perceived as a co-mingling of church and state.

Early Saturday, fire crews responded after his single-engine plane was spotted in an area off Meyer Road, just north of Pleasant Grove Road, according to Marengo firefighter Joe Taylor.

The Zenair CH 601 crashed under “unknown circumstances” sometime between Friday night and Saturday morning, according to Taylor and FAA spokesman Tony Molinaro.

Authorities said late Monday that the aircraft was a manufactured model, not a home-built version.

A Monday autopsy found Mr. Sherman, of Poplar Grove, died of multiple injuries from the mishap, which is being investigated by the FAA and NTSB.

In the 1980s and 1990s, Mr. Sherman was constantly in the headlines for atheism activism.

As Sun-Times columnist Richard Roeper put it in 1998, “He has battled towns from South Holland to Deerfield to Zion to Palatine to Highland, Ind., and Wauwatosa, Wis., over public displays of religious symbols on water towers, on government property and on official village seals.”

Mr. Sherman also filed suit against the Boy Scouts after he and his son, Richard, were denied membership because they refused to recognize a “duty to God.”

The relationship between Mr. Sherman and his son made headlines in 1998 for personal rather political reasons. He was convicted of domestic battery after he struck his then-16-year-old son, and later spent a brief time in jail.

“I wanted to put the fear of God in him,” Mr. Sherman told police.

He once told Roeper he’d known he was an atheist since he was 9. “It became a big deal when I was about 13 and I didn’t want to go to Hebrew School anymore. When my parents asked why, I said, ‘Because I’m an atheist.’ I don’t believe in make-believe, so I don’t believe in God.’’

He attended National-Louis University, Northwestern University and Harper College, according to a candidate questionnaire he submitted to the Daily Herald.

This year, he ran unsuccessfully for Illinois’ 5th Congressional district seat as the Green Party candidate. He chaired the Cook County Green Party in 2012. In 2008, he ran as a Green candidate for Illinois state representative in the 53rd district. And he once hosted the Rob Sherman Show on AM 1530 WJJG Chicago and a weekly talk show on WSSY-AM (1330).

Mr. Sherman’s philosophy, on matters from the practical to the ecclesiastical, was summarized on robsherman.com, a website created to drum up donations for his planned 2018 congressional run in the 12th district. On it, he promoted capitalism while calling for a fight against climate change. He promised to battle gender and LGBT discrimination, as well as red light cameras, or as he put it, “Revenue Scam Cameras.”

And, he emphasized the issue that brought him to public attention. “I will sponsor legislation to get ‘In God We Trust’ off of our money, remove ‘One Nation Under God’ from our Pledge of Allegiance, eliminate the National Day of Prayer and repeal Christmas as a federal holiday,” he wrote next to his likeness on a coin proclaiming “In Rob We Trust.”

Though sometimes described as “pesky,” he also drew grudging admiration from opponents who found their views occasionally intersected with those of Mr. Sherman. His political website, laced with a quixotic tone some found refreshing compared to traditional messaging, helped explain his endurance in the public eye.

On the site, he wrote this about his 2016 bid for Congress: “Even though 14,657 votes were not quite enough to win the General Election, this huge number of votes demonstrates widespread support for my agenda of capitalism, secular government and electoral reform. Congratulations to Democrat Mike Quigley for winning re-election as Congressman from the 5th District of Illinois. Mike received slightly more votes than I did, which was a little over 200,000 votes.”

His business, which assisted people in building light airplanes from kits, was located at Poplar Grove Airport. “Rob Sherman Airplanes helps you build your own airplane by providing you with a place to build your Zenith kit airplane, the tools to build it, the knowledge and expertise on what to do and counseling on what to buy, all at a surprisingly low cost,” said his aviation site. http://www.robsherman.com/airplanes/home.htm

It proclaimed: “Just think: No more airline fees! No more TSA hassles! Fly when you want! No more 20 cent-per-mile tolls from the Illinois Tollway! No more highway construction delays! No more red light camera scams. Imagine: You, a PILOT!, with your own airplane. Wouldn’t that be great! You CAN do it.”

In 1978 he married his wife Celeste, whom he called “the world’s most perfect wife of all time.” In addition to his son, he is survived by a daughter, Dawn.