Theories suggesting that UAPs can be explained by ordinary, mundane, or conventional phenomena, objects, or processes, without invoking exotic or extraordinary explanations.

Theories proposing that UAPs are the products of hidden, ancient, or technologically advanced Earth-based civilizations or non-human entities residing on Earth, often in secluded or inaccessible locations.

Theories suggesting that UAPs are spacecraft, probes, or manifestations of advanced extraterrestrial civilizations visiting Earth from other planets, star systems, or galaxies.

Theories proposing that UAPs are entities or objects originating from a higher-dimensional space (hyperspace) that can manifest in our perceivable three-dimensional reality.

Theories based on the concept of branes (short for "membranes") from string theory, suggesting that UAPs are manifestations or objects from higher-dimensional branes interacting with our own three-dimensional brane.

Theories proposing that UAPs originate from parallel universes or alternate realities within a larger multiverse framework, occasionally intersecting with or manifesting in our own universe.

Theories suggesting that UAPs are time-traveling craft, entities, or phenomena from the future or the past, capable of navigating through temporal dimensions.

Theories based on the concept of scale invariance, proposing that UAPs are manifestations of objects or entities that can operate across different scales of reality, from the microscopic to the cosmic, while maintaining similar properties and behaviors.