Chicago police said the 33-year-old man was apprehended on Midway property near runway 31 about 4:45 p.m.
Police said he hopped a barbed wire fence near 55th Street and Lorel Avenue, where his jacket and shirt became tangled up in the fence.
Investigators said he was seen walking on the runway, then later took off his clothes and climbed onto a wing of a private jet. He was arrested after about 15 minutes.
RELATED: As US travel restrictions ease, Mayor Lightfoot touts new features at Chicago airports
Witnesses said he appeared to be intoxicated. Police said he was transported to MacNeal Hospital for minor injuries and a mental health evaluation.
This is the second time someone was able to gain access to a restricted area from the outside in 6 months according to Chicago police. The other happened at 57th and Cicero in September 2021.
"You look for trends. If this happens once or twice or three times and then you think there might be an area of security you might want to bolster up," said Professor Robert Eric Jones, Lewis University College of Aviation, Science and Technology Associate Dean.
Jones said he is shocked someone was able to get that far. But, "the security apparatus that they have in place at Midway did actually work. And there wasn't any significant harm."
"Fifteen minutes for an active individual on the tarmac is not tremendously long. Rarely will they get out there last the tarmac," Jones said.
University of Illinois risk assessment specialist Professor Sheldon Jacobson said this shows improvements to security are needed.
"Airport security is a system of layers and each layer has potential points which can be breached," he said. "That bad intent was neutralized through one of the layers."
Charges are currently pending. Area One detectives are investigating the incident.