In the United States, the FAA establishes guidelines for security procedures in domestic airports.
Airlines are then responsible for handling checkpoints and luggage screening.
Foreign carriers also must obey FAA rules when flying to or from the United States. But the FAA has no jurisdiction on setting guidelines abroad. That chore is handled by the Montreal-based International Civil Aviation Organization, a United Nations agency. It sets safety standards but plays no enforcement role, leaving implementation to its 185 member countries, which include Nepal and India. But the countries, for obvious reasons, provide little useful or reassuring data about specific security practices.