While lakefront crowds thrilled to the likes of the Blue Angels, there was another show going on in the skies above the so-called "safety box" of restricted airspace: For the first time in recent memory, commercial air traffic was flying within sight of the show planes during Sunday’s show.
A handful of big jets, including at least one Boeing 747, were photographed passing not far from show center.
But while most people didn’t notice, the Federal Aviation Administration said traffic was re-routed near the show for safety reasons.
"We had a shift in wind," explained Elizabeth Isham Cory, the spokesperson for the FAA’s Great Lakes Region.
When that happened, she said controllers dropped the ceiling on the restricted airspace of the air show safety box. Later, they were able to run commercial traffic through the box.
"You can’t land with the wind at your tail," said Rob Mark, a former commercial pilot and current editor of the aviation website Jetwhine.com. "It’s a dangerous situation."
Mark said to land into the wind, planes were likely lined up over the lake and near the show.
"In Chicago, O’Hare pretty much rules air traffic," Mark said. "When O’Hare needs something, O’Hare gets what it wants."
The Mayor's Office of Special Events and the city's Department of Aviation referred all questions about Sunday's show to the FAA.
And while there were no safety concerns, the move likely gave some an even better show.
"If I were in the plane, it would have been cool to see, seeing an air show for free right down next to you," said spectator Patrick Scully of Schaumburg.
