Just when you thought it was safe to fly away on a summer holiday, along comes this almost indecently gleeful reminder that the sky, even more than the sea, can be terribly unforgiving of mistakes. If the author (a freelance journalist) is not on a par with Arthur Hailey as a storyteller, he's at least as good as the pop novelist at evoking the workaday routines of a commercial aviation hub, in this case New York City's John F. Kennedy International Airport. Wittingly or not, however, Kaplan accentuates the negative in his episodic take on JFK, starting with the inadequate roadway system that guarantees traffic jams at almost any hour of the day or night around the five main terminal buildings, which handle over 31 million passengers a year. He goes on to provide chilling recaps of fatal jetliner crashes at JFK (and elsewhere), segueing into accounts of how emergency crews are trained to deal with and avert such disasters. Covered as well are the air-traffic controllers, cab drivers, cops, customs inspectors, firefighters, flight attendants, immigration officials, mechanics, pilots, and other specialists needed to keep the Big Apple's gateway to a wider world operating. Of particular interest is the enterprising physician, now retired, who had JFK's lucrative medical concession, which treats drug smugglers who have ingested their contraband as well as the victims of heart attacks, industrial accidents, and a host of assorted mishaps. Kaplan probes the reasons why JFK's poorly protected cargo facilities have been a magnet for organized crime; and on the strength of a free ride to Heathrow in the SST Concorde, he explores fear of flying -- or, more precisely, crashing. While the absorbing text includes statistical assurances as to air travel's relative safety, its behind-the-scenes reportage on JFK is not calculated to instill much confidence in either frequent or occasional fliers.