CHICAGO (CBS) — Airlines across the United States are scrambling to make schedule changes, after the FAA issued an emergency order grounding all Boeing 737 Max 8 and Max 9 aircraft, in the wake of two fatal crashes.

The order comes at a busy time for airlines, with many colleges and universities heading into spring break.

Southwest Airlines, the largest carrier at Midway International Airport, has more than 30 of those planes, accounting for nearly five percent of its fleet.

Many college students lined up at check-in counters at Midway on Thursday, while Southwest works to minimize flight cancellations with part of its fleet sidelined.

From family vacationers to spring break revelers to a track team headed to a meet in Texas, Midway played host to all kinds of college students setting course for warmer climates on Thursday.

“It’s just a really good break to split things up a bit,” said University of Northern Iowa freshman Caleb Rheingans, heading to Mexico for spring vacation.

While students look forward to time away from lecture halls, airlines are scrambling to adjust their schedules.

The U.S. joined several other countries in grounding 737 Max 8 and Max 9 jets, leaving Southwest Airlines with no choice but to sideline 34 of their aircraft.

Antwanique Kinsler, a Chicago State University freshman, said it was definitely the right call to ground those planes, after Max 8 jets were involved in two similar deadly crashes in the past six months.

“It is a safety hazard,” Kinsler said.

On Sunday, Ethiopian Airlines flight 302 crashed near Addis Ababa, Ethiopia, killing all 157 people on board. In October, a Lion Air flight crashed into the Java Sea off Indonesia, killing all 189 passengers and crew.

Both crashes involved Max 8 aircraft, which nosedived shortly after takeoff. However, there has been no evidence that the two crashes were caused by the same issue.

Despite the idea of having to cancel or re-book travel plans, several travelers at O’Hare agreed safety comes before spring break fun.

“I think it is a good idea. They should ground all of them, check what’s going on,” Chicago State University freshman Michael Brown said.

As the reconfiguring continues, Southwest is urging customers to book online instead of calling. Many Southwest customers had taken to Twitter to complain about lengthy hold times on the phone.

“I personally like Southwest a lot as an air company, and I’m glad that they are taking measures to do this,” Loyola University senior Joe Harvey said.

American Airlines and United Airlines, the largest carriers at O’Hare, also have dozens of Max 8 and Max 9 in their fleets. American has 85 Max 8 flights per day. United has 40 a day, although none out of O’Hare or Midway.

Before the FAA grounded all Max 8 and Max 9 planes, the agency had ordered Boeing to begin safety-related software enhancements on those aircraft by next month.

There are 74 of these planes used in the United States and 387 worldwide. The changes to the Boeing jets have been in the works since the Lion Air crash in October.

One of the changes includes updates to the anti-stall system, which automatically points the plane’s nose down if sensors find the plane could be in danger of losing lift.