Authorities said the small Cessna airplane fell apart in the air.
On Monday, Price County Sheriff Brian Schmidt released the identities of the victims: Kevin King, 70, of Bensenville; James Francis, 63, of Norco, Calif.; Kyle DeMauro, 21, of Bensenville; Thomas DeMauro, 56, of Bensenville; Charles Tomlitz, 69, of Addison; and George Tomlitz, 45, of Brookfield.
Their Cessna 421 took off from Waukegan headed to Canada for a fishing trip. The Price County Sheriff's Office says the airplane crashed at 3:21 a.m. Saturday in a wooded area in Catawba.
Thomas DeMauro and Chuck Tomlitz worked for the Bensenville School District 2. Teachers and staff in the district are planning a memorial on Thursday. Tomlitz was the school district's maintenance director and DeMauro was a physical education teacher.
The men were with their sons and it was a trip that they had done before.
DeMauro grew up in Bensenville and spent his career as a coach and physical education teacher there. His 21-year-old son Kyle also lived in the family's Bensenville home.
The group also included Tomlitz and his son George, as well as another friend who lived in California.
Next door to the DeMauro's lived King, a former fighter pilot who was flying the Cessna they were in when it crashed. He owned a tool-and-die shop in Bensenville and was one of the first residents in the neighborhood. Friends said King was an extremely skilled pilot who owned several planes.
"IN-FLIGHT BREAK UP"
Eric Weiss, of the National Transportation Safety Board, said Monday the debris from the plane crash suggests there was an "in-flight break up."
NTSB investigators say there was a discussion between the pilot of the plane and air traffic controllers about "local weather phenomenon" shortly before the crash. Weiss said investigators are trying to determine if weather caused the crash.
A community came together on Monday to remember six men killed in a plane crash. A coach and PE teacher at Tioga Elementary, Thomas DeMauro was remembered for the enthusiasm he brought out in his students.
Thomas DeMauro grew up in Bensenville and that's where he spent his career. His death was a great loss for all of those with a connection to Tioga Elementary.
"He didn't care who you were, where your background was from. He treated you with respect," said Ron Rowe, father and grandfather of former students.
"He was really nice and he kept us moving and active and he always encouraged us. and he always put a smile on our faces," said student Marina DiTullo
Students and parents left notes of remembrance at Tioga Elementary on Monday night.
"He was very bright and positive and he just made everyone's day," said former student Alfredo Guadarrama.
The Associated Press contributed to this report.