There have been several arrests and convictions of planned attacks, but our security forces are doing a great job in preventing them.
This attack may well change security at airports. At the moment anyone can walk into a departure lounge without being scanned.
It's always been a weak point. The problem is though that there will always be a point were un-scanned people have to queue up to be scanned. Of course you can insist hold luggage is sent on ahead, but you'll still have a queue for a scanner somewhere.