A system for intelligent non-disruptive airspace integration of unmanned aircraft systems (UAS) is disclosed. The system includes an onboard positioning system and altimeter that determine a current position and altitude of the UAS. Under normal conditions, the UAS remains in inert mode: a transceiver listens for and decodes transmissions from nearby aircraft and ground-based traffic and control facilities. If certain conditions are met (e.g., proximate aircraft, altitude ceilings, controlled or restricted airspaces) the system may declare an alert mode. When in alert mode, the transceiver broadcasts position and identifier information of the UAS to alert neighboring aircraft to its presence. Intelligent transmission strategies regulate the power level or rate of alert-mode transmissions to reduce spectrum congestion due to high UAS density. Alert-mode transmissions continue until the underlying conditions change and inert mode is resumed.