Different classifications for FO Debris are defined. FO Debris may be classified as animate (biological) or inanimate (non-biological) objects. It may be also defined as ground or airborne debris. Moreover, it may be defined as internal (to aircraft) or external debris. Finally, it may be classified based on matter (material, colors, and size).

Inanimate (inorganic or non-biological) foreign object debris include personal items like coins, pens, mobiles, watches, eyeglasses, hats, gloves, soda cans, paperwork, and others. FO debris may also include aircraft and engine parts like fasteners, fuel caps, oil sticks, metal sheets, and technician tools like wrench, socket, hammer, etc. Other debris related to the airport may include lights, signs, rocks, sand, pebbles, and loose vegetation. Moreover, FO Debris may include ground support equipment (GSE) like maintenance equipment, fueling trucks, tow tractors, and catering supplies like spoons, food wrappers, freight pallets, and baggage tags and pieces. In addition, adverse weather may add additional debris like hail, snow, rain, sand, and volcanic ash. Concerning military airbases debris may contain bomb-damaged runways, bomb fragments, parts of a refueling basket during refueling process. Recently, FO Debris included drones, Unmanned Aircraft Vehicles (UAVs), and parts of space vehicles that reenter the Earth orbits like the core stage of the Chinese Long March 5B rocket that crashed in the Indian Ocean north of the Maldives on May 8, 2021. Finally, helicopters flying close to the ground may generate sandstorms if flying in deserts or snow and icy particles when flying near snowy terrains.

Animate foreign object debris (living organisms) may be airborne like birds and bats, insects, or ground ones, including mammals (deer, moose, etc.) and reptiles (crocodiles, alligators, and snakes), grass, and plant fragments. The most precious debris is humans who are in rare cases sucked into aeroengines.

Foreign Object Damage is the damage caused by the foreign object debris to aircraft parts and equipment and may cause human injury or death. Damage to aircraft parts could be in the form of punctured airframes, torn or punctured tires, worn compressors and fans, nicked turbine, or propeller blades, and, in rare instances, complete damage to aircraft or engine failure. The injury to airport employees may be caused by debris propelled by the jet blast, propeller, or rotor wash. FO Damage may cause trouble to airports, airlines, and military bases. In brief, the damage of flying vehicles may be categorized into four types namely: acceptable with no maintenance requirements, acceptable with some minor repair, unacceptable with either in-site repair or module removal for shop repair, and catastrophic.