Early Friday evening, Chicago-based United said it would be canceling 2,300 flights this weekend to and from the east. Other airlines are doing the same.
Brooke Byrnes had to cut short her visit to her sister here in Chicago to get back to Washington DC.
"My flight was supposed to leave tomorrow but it was cancelled, so I'm trying to get home before the storm hits," she told ABC7.
Heather Silveira suspended her job search in New York Friday afternoon to ride out the storm with her aunt in Chicago.
"It's frustrating, so hard leaving because it's like you don't know if it's gonna be bad or if I'm just leaving for nothing, but it's better to safe rather than be caught in a storm while I'm apartment hunting too," said Silveira.
Earlier on Friday, many travelers at O'Hare were catching flights to New York and Washington DC. Others were arriving back home after being forced to cut short their vacations along the East Coast.
"We were notified 'cause we rented a beach house with the family and we were notified that we had to get out by a certain amount of time," said Jeffrey Parnell of Lake Forest.
"I got the first flight out today. I could have gone later this afternoon or tomorrow evening, but I wanted to get out and I saw other people trying to get out," said Greg Thompson, who arrived at the airport from Virginia.
Some airlines are waiving change fees.
Meanwhile, many emergency crews from across the country, including Chicago, are headed east to help with the potential devastation.
The trip will be long. But Commonwealth Edison crews are expecting to endure even longer days once Hurricane Irene makes land fall. On Friday morning, 100 crews loaded up in Chicago for a trip to their sister power company in Philadelphia. They will have training in Philadelphia then help restore service to areas impacted by the storm.
"Work safely, watch out for each other while you're out there. We are not sure what you're going to come across," said Dan Galovich, ComEd.
In Northbrook, 35 Allstate employees have already left for the East Coast. Those who remain in the Chicago area are supporting and coordinating efforts.
"Every department, every employee in the Allstate home office is prepared to support and is supporting our response," said Mark McGillivray, Allstate.
Allstate has over a 1,000 people following the storm and preparing to get clients money and estimates as soon as possible after the storm.
"Staging them initially in Charlotte, North Carolina and then from there we have been moving them up the East Coast, being prepared to get enter whatever the damaged areas as soon as it is safet to get in," said McGillivray.
Bloomington-based State Farm has catastrophe teams on standby. The mobile catastrophe facility brought to Chicago after a summer hail storm will be leaving Sunday with eight other mobile units from Illinois.
"We will have claim reps working right out of there. People can ask questions, file the claim and get possible checks and that type of thing," said Missy Lundberg, State Farm.
All of the crews leaving the Chicago area are monitoring the storm to plot their final destinations. The insurance companies know where their customers are and can pin point the teams to go directly to the customers. The ComEd crews will start in Philadelphia but won't know their destination for a couple of days.
Chicago Police Superintendent Garry McCarthy said he thinks New York will weather things just fine, but if help is needed, help will be there.
"Post Katrina, everybody went down to New Orleans so we do this constanntly. You know mutual aid, and if necessary, I'd be glad to do that," said McCarthy.
Chicago area Red Cross, Salvation Army, and other relief agencies have already sent staffers east while volunteers are at the ready depending upon how Irene behaves.
Hurricane Irene could have an economic impact here in the Chicago area. Experts say the storm could affect gas prices with 10 percent of the nation's capacity off the New Jersey coast.
"Some prices would like increase, particularly if there is destruction to gasoline refineries oil refineries," said David Mirza, economist, Loyola University's School of Business.
Mirza says a natural disaster, in a strange twist, could help the economy.
"We would be willing to spend the money to make the construction, build the buildings back...and this will be good," he said.