Currently people who are catching a connecting flight – described as being in transit - do not have to have go through security in some countries. But the alleged attempt by Nigerian Umar Farouk Abdulmutallab to try to bring down the Detroit-bound flight, has prompted a major review of airport security around the world. John Greenway, says "People are obviously asking about the Detroit bomb scare - would this have picked it up? Potentially it would have picked it up - obviously there needs to be some more testing before we can say categorically yes."