"Suggestions in a Rand security study are too costly to implement any time soon, officials say. Despite warnings by security experts that long lines at Los Angeles International Airport are vulnerable to a terrorist attack, airport officials have concluded that the staff cannot be added to significantly shorten queues in the next few years. Rand Corp. recommended last fall that airlines and federal officials hire more people to speed travelers from sidewalks and terminal lobbies into the more secure gate areas as the quickest and cheapest way to protect LAX passengers. But in documents obtained by The Times, the airport's...