Flight 441 was on its way from Chicago to Salt Lake City, when the woman went into labor.
The flight was diverted to Denver, but the baby boy didn't wait.
The Southwest Airlines flight was cruising about 100 miles north of Denver when the pilot asked, "Is there a doctor on board?"
"She was a trouper. She was having some pain. She was actually right in the seat in front of me, and I didn't know it until I found out she was in labor," said Saran.
Saran, who is from Naperville, was on his way to a ski vacation when the pilots asked for help.
The crew set up a make shift delivery room in the back of the plane and mom-to-be and doctor went to work.
"When I first saw the head coming out, I thought, great, at least it's not the back end. That would have been a problem. The baby came out very quickly and easily and it was a very normal delivery," said Saran.
When the baby boy made his entrance into the world, Dr. Saran had to improvise.
"I used my shoe strings, looked around for strings. I pulled the shoestrings out of my shoes, so that baby's walking around with one of my shoestrings on its umbilical cord," said Dr. Saran.
Passengers applauded the mom, doctor and newborn.
"Then the pilot got on and when he announced, everybody started clapping and cheering-- it was pretty intense," said Brandon Morse, passenger.
"We started out with 150 and we ended up with 151," said Weldon Robinson, passenger.
Pilots diverted to Denver where paramedics met the plane.
Mom, dad, baby and the couple's other children were all taken to a hospital.
"The mom and baby are doing fine," said Joanna King, hospital spokesperson.