InCanada and theUnited States,DVFR is anaviation acronym forDefense Visual Flight Rules. It refers to one type offlight plan that must be filed for operation within anAir Defense Identification Zone (the alternative being anIFR flight plan).
Flight rules under a DVFR plan are not substantially different from under aVFR plan, except that the pilot is required to notify Air Traffic Control prior to deviating from a DVFR plan while inside anADIZ, and that two-way radio communication is required while inside the ADIZ.