The bombers of the airport in Brussels exploded their bombs in the check-in area (before the passport control and even further from the baggage scanners). When the airport reopened, they had pushed the security as far back as they could.
There are now military+police checkpoints for cars before you get near the airport, just off the highway exits. It would be difficult to get a car bomb past. You have to get dropped off in a specific car park and walk up to 2 km to get to the security queue to get into the temporary airport buildings.
The queue for the next security check, where they check bags is about 500m long. Everyone is in a very long, thin queue. If there were bombs in the bags to be checked in, the best they could do is explode in the queue outside of the building, which would cause little damage, except to the few within 10m or so.
The end result is a nightmare of an airport, with people avoiding it and not flying. Passenger numbers are way down. A friend who flew recently took 4 hours to get through the security lines and to his flight. He just made it, even though it was a morning flight, and he arrived 4 hours in advance, at around 6am. I would hate to see the queue at 10am or later.
It hasn't crippled the economy, but has really screwed the operators of the airport and all of the airlines using it.