Advanced aerial and transmedium craft are often grouped under a single category of “exotic propulsion.” This paper introduces a diagnostic framework that distinguishes plasma-based systems from coherence-based systems through observable field behavior rather than inferred mechanisms. Plasma systems achieve functionality through active regulation of energetic instability, while coherence systems operate through intrinsic phase alignment and geometric configuration. These two stability classes produce distinct electromagnetic, environmental, biological, and transition-state signatures. By focusing on measurable phase behavior, curvature interaction, and perturbation response, this paper provides a method for identifying coherent craft independent of origin, intent, or technological mythology. coherent craft, plasma propulsion, phase stability, electromagnetic coherence, UAP detection, field geometry, intrinsic stability, regulated stability, phase alignment, curvature matching, inertial decoupling, transition signatures, EM noise, torsion fields, spacetime curvature, non-Newtonian flight, field propulsion, coherence technology, plasma confinement, phase variance, environmental coupling, biological effects, quiet propulsion, advanced craft classification, stability classes, coherent fields, plasma turbulence, phase metrics, craft detection, EM signatures, coherence theorem, field continuity, geometric alignment, force-free translation, transmedium travel, phase behavior, curvature cancellation, sensor diagnostics, advanced aerospace, coherent systems, plasma systems, stability discrimination, phase noise, silent flight, craft transitions