The six others who were part of the excursion flew in another plane that landed safely at a larger airport in nearby Columbus instead, Meyerrose said.
The Horans have four daughters, and the Butzens have two sons.
"They leave behind six children who are grieving and hurting over the loss of their parents," family friend Brian Wenning said at a news conference with local investigators.
The plane ended up in a wooded area about 40 miles southeast of Indianapolis. The Federal Aviation Administration said the single-engine Piper had been cleared to approach the airport but never arrived. Someone called the sheriff's department at 6:19 p.m. Sunday saying he believed he had seen a plane crash. The FAA said it had been tracking the plane and lost contact about two miles from the airport.
The plane apparently crashed in a field, then went down a steep hill before stopping in a wooded area.
WTHR-TV reported that Horan was an instrument-rated pilot, so he was allowed to fly in poor weather.
The Greensburg airport's pilot-controlled runway lights are activated by radio but were not on at the time of the crash, Meyerrose said.
The weather hampered the search for the wreckage, which wasn't found for about four hours, Meyerrose said. National Transportation Safety Board investigators were traveling Monday to the scene about 40 miles southeast of Indianapolis.
The Catholic Archdiocese of Indianapolis released a statement from Auxiliary Bishop Christopher Coyne saying the two couples were parishioners at St. Mary Parish in Greensburg.
"In 2010, the Horans were co-chairs of the annual United Catholic Appeal, which raises nearly $5 million each year for ministry needs throughout the archdiocese. They travelled to every corner of the archdiocese to raise funds for ministry needs. Donald also was a member of the board of directors of the Catholic Community Foundation and served as president of the foundation in 2011," the statement said. The foundation oversees 407 endowments with nearly $138 million in assets.
Don Horan is listed the chief executive officer of Greensburg-based Collection Associates Inc., a collection service for the health care industry.
A neighbor told The Indianapolis Star that Horan was community-minded and generous.
"I'd heard he was traveling with his wife. His whole family is great. It's pretty well known he gave a million dollars to help build a new Catholic school down here a few years back." said Paul Walston, 84.