The plane departed before two bombs went off at Brussels Airport. A third bomb went off at a metro station in the city about an hour later. At least 30 were people reported dead and hundreds were injured.
The Islamic State terrorist organization claimed responsibility for the bombings Tuesday.
Airport officials in Sanford said the flight was the only one from Brussels to make it to the U.S. Tuesday. It was also one of the few to take off before the explosions and the subsequent hike in security.
Passengers were separated from their bags, which were checked for explosives by bomb-sniffing dogs.
The plane's 269 passengers were allowed into the terminal to be processed through customs while their bags remained on the tarmac.
Law enforcement did not immediately say what security concerns they had about the plane.
A flight to Brussels from Sanford was scheduled for 2:40 p.m. but passengers were rerouted to Miami and would be flown into a different Belgian city, officials said.
Passengers on the flight from Brussels were aware of the events that took place after their plane departed and were eager to disembark and check on loved ones, officials said.