Rules of the air and rules of the sea occupy different legal and regulatory regimes but share commonalities focused on safety and security of navigation, the demarcation of territorial sovereignty and governance by international treaty. Rules of the Air have their genesis in the Convention on International Civil Aviation (Chicago Convention) and are administered by the International Civil Aviation Organization (ICAO). Safety, efficiency, and standardization are the core principles guiding the Rules of the Air. The framework emphasizes clear airspace designations, navigation protocols, and protocols for communication between aircraft and air traffic control. Rules of the Sea comprise a complex set of regulations governing maritime navigation, trade, environmental protection, and territorial claims administered by the International Maritime Organization (IMO). The United Nations Convention on the Law of the Sea (UNCLOS) serves as the fundamental legal framework for maritime activities, establishing guidelines for territorial waters, contiguous and exclusive economic zones, and the exploitation of marine resources. Technological developments have driven the evolution of rules in distinct ways, adapting to the different environments and resources of the air and the sea. Having no exploitable resources in the air, airspace management relies heavily on communication and navigation technology, while maritime operations, which, while involving navigation on the seas, must also address the use of maritime resources and regulate territoriality and jurisdiction. This article compares the rules governing airspace, and the regulations governing maritime activities, addressing the distinct characteristics, historical development, regulatory bodies, and key principles that underpin these two sets of rules.