“ABC News reported on Wednes­day that teams equipped with radi­o­log­i­cal sen­sors were patrolling Boston amid a pos­si­ble ‘dirty bomb’ threat, but local police said they had no infor­ma­tion.”Reuters (Jan­u­ary 19, 2005)

You can file these in the remarks sec­tion of your flight plan, or for bet­ter effect, use them as your call­sign! From the FAA rulebook:

• SAMP – Air­borne radi­a­tion sam­pling aircraft
• FLYNET – Air­craft trans­port­ing Nuclear Emer­gency Search Team
• SCOOT – Air­craft evac­u­at­ing high-ranking gov­ern­ment official
• NAOC – National Air­borne Oper­a­tions Cen­ter (aka “Night Watch,” “President’s dooms­day plane”)
• GARDEN PLOT – clas­si­fied (related to mil­i­tary sup­pres­sion of civil upris­ing inside U.S.)
• LIFEGUARD – Flight has life-or-death priority
• OSY – OPEN SKIES Russ­ian treaty obser­va­tion air­craft (obsolete)