Man 'lived 3 months at Chicago airport'

A California man police say claimed to be too afraid to fly due to COVID-19 hid out for three months in a secure area of Chicago Airport until his weekend arrest, prosecutors say.

In court on Sunday, prosecutors said Aditya Singh, 36, arrived at O'Hare International Airport in Chicago on a flight from Los Angeles on October 19.

They allege he has lived in the airport's security zone ever since, without detection.

Cook County Judge Susana Ortiz reacted incredulously when a prosecutor detailed the allegations.

"You're telling me that an unauthorised, non-employee individual was allegedly living within a secure part of the O'Hare airport terminal from October 19, 2020, to January 16, 2021, and was not detected?" Ortiz said.

"I want to understand you correctly."

Early on Saturday afternoon, two United Airlines employees approached Singh and asked to see his identification.

The airport ID badge he showed them actually belonged to an operations manager who had reported it missing on October 26.

Assistant State Attorney Kathleen Hagerty said Singh reportedly found the badge in the airport and was "scared to go home due to COVID".

She told the judge other passengers were giving him food.

Singh lives in the Los Angeles suburb of Orange with roommates and does not have a criminal background, according to Assistant Public Defender Courtney Smallwood.

As a condition of bail, Ortiz barred Singh from stepping foot in the airport again if he is able to post the $US1000 ($A1,302) he needs for his release. He is due back in court January 27.

"The court finds these facts and circumstances quite shocking for the alleged period of time that this occurred," the judge said.

"Being in a secured part of the airport under a fake ID badge allegedly, based upon the need for airports to be absolutely secure so that people feel safe to travel, I do find those alleged actions do make him a danger to the community."