Summary: Pursuant to a legislative requirement, GAO reviewed Federal Aviation Administration's (FAA) efforts to comply with the Aviation Security Improvement Act and develop and implement new security technologies. GAO noted that: (1) FAA did not meet Congress' goal to deploy new security technology at airports by November 1993; (2) although several explosive detection devices could improve airport security, technical problems have slowed their development; (3) considerable time will be needed to implement the new technologies at high-threat domestic and international airports; (4) although improving aircraft survivability through blast resistant luggage containers and hardened structures shows promise, it is uncertain when these technologies will be in widespread use; (5) FAA needs to improve its certification process for new explosive detection devices because its current process does not adequately test the new systems to ensure their performance and reliability; (6) FAA does not believe that on-site testing should be part of the certification process, since such testing will likely add time and costs to the process; (7) airport testing may enable FAA to gain the confidence of the airline industry; (8) FAA believes that the airline industry should evaluate the software used in new explosive detection devices, since these systems rely heavily on software to indicate the presence of explosive devices; and (9) the costs to acquire new security technology could range from $250,000 to over $1 million per device.