The chapter considers the application of ontology models enriched with external resources for intelligent planning of a UAV swarm mission. The relevance of ontologies for formalizing knowledge about missions, environment, and threats is substantiated. A method for enriching ontologies from online knowledge bases, encyclopedias, dictionaries, and other open sources using the information field concept for preliminary information assessment and processing is proposed. A methodology for adaptive ontology updating is presented. The proposed approach using online external information resources allows to take into account the dynamics of updating current information about research objects, reduces ontology update time, provides high-quality knowledge for UAV swarm self-organization, movement coordination, threat detection, and flexible response to the external environment.