The elderly couple who were woken from sleep when a small plane crashed into their Chicago home early this morning are baffled by what happened, but are safe, their son said today.

The couple is now staying with a neighbor.

"They're okay, a little confused as you might, you know, think," the couple's son Rick Rolinskas told ABC News affiliate ABC 7 in Chicago. "Thank God. … They got out safe."

M. Spencer Green/AP Photo

He said his parents both have Alzheimer's disease.

The crash occurred near Chicago Midway International Airport around 2:45 a.m. today and involved an Aero Commander 500 cargo jet, an FAA spokeswoman said. The plane had just departed the airport when the pilot reported engine problems.

Pilot dead after "homemade" plane crashes in Australia neighborhood.

3 believed dead after Illinois plane crash.

Stolen plane crashes on White House lawn.

As the pilot tried to return to the airport, the plane crashed about a mile away, into Raymond and Roberta Rolinskas' house.

Chief Michael Fox of the Chicago Fire Department said the couple were in a bedroom next to the living room, where much of the plane ended up.

"The wreckage from them was about 8 inches away from them," Fox said today.

The pilot, who was not identified, was killed.

Luz Cazares, a neighbor, helped Roberta Rolinskas get out of the house. Police helped her husband, Raymond, escape.

"They didn't hear anything. They didn't even really know what happened," said Brett Rolinskas, the couple's grandson. "They couldn't see anything so they didn't know what happened."

The FAA said its investigation into the crash, which will be led by the National Transportation Safety Board, could take up to a year or more.

ABC News' Whitney Lloyd and WLS-TV contributed to this story.