CURBSIDE
Checking passenger bags at the curb makes it more difficult to match a bag with its owner, and easier to get potentially lethal suitcases on to a plane. Last week, the FAA suspended curbside baggage check-in.

Scroll for more >>
CHECK-IN
"Has anyone else had access to your bag?" Has anyone ever answered "Yes"? Checking for a photo ID is standard procedure, but the practice is erratic. Checked bags aren't always X-rayed.
RESTAURANTS
Concession areas are a security question mark in many places. Most workers in the terminal currently faced no screening or background checks. Concourse workers face more stringent standards since they work beyond the security screening area. But at some airports, any vendor can gain access to the ramp and the plane without much difficulty.
SECURITY
Security companies are contracted by airlines to check passengers and their bags for weapons and other dangerous items. There are FAA standards, but no effective certification. Screeners are notoriously undertrained and underpaid — as low as $6 an hour — leading to rapid turnover rates, as high as 400%.
BOARDING
Passengers checking in at the gate face less scrutiny. Another big worry: passengers off connecting flights who may not have been adequately screened at a previous airport and bypass screening at the connections. New regs last week will allow only ticketed passengers in the boarding area.
ON THE TARMAC
Myriad people have access to a plane parked at the gate: cleaners, caterers, mechanics, refuelers and baggage handlers, each supervised by a different entity with its own standards. FAA regs now say anyone who touches the plane must have a criminal background check, but large numbers of workers are seasonal, some even undocumented, who may not been subject to checks. Unauthorized people can easily gain access via one of the many private jet companies that have more lax standards for entrance and little security. A teenager cut through perimeter fencing at Logan, and boarded a flight in 1999.
TIME graphic by Joe Lertola; Source: Dr. Todd Curtis, AirSafe.com