In the USAF the position of boom operator is a position held by an enlisted aviator

Aviator

An aviator is a person who flies an aircraft. The first recorded use of the term was in 1887, as a variation of 'aviation', from the Latin avis , coined in 1863 by G. de la Landelle in Aviation Ou Navigation Aérienne...

, (rank Airman Basic

Airman Basic

Airman Basic is the lowest enlisted rank in the United States Air Force , immediately below Airman. The pay grade for Airman Basic is E-1.As opposed to all other USAF enlisted and officer ranks, Airman Basic has no rank insignia affiliated...

 through Chief Master Sergeant

Chief Master Sergeant

CMSgt ChevronChief Master Sergeant is the ninth, and highest, enlisted rank in the U.S. Air Force, just above Senior Master Sergeant, and is a senior non-commissioned officer. The official term of address is "Chief Master Sergeant" or "Chief".Attaining the rank of Chief Master Sergeant is the...

) who is responsible for safely and effectively refueling other aircraft while in flight. The official Air Force title for boom operators is "In-Flight Refueling Technician" but this title is usually reserved for formal paperwork such as Air Medals. The title "boom" is more commonly used. The name boom operator implies that one "operates a boom" which in the case of a tanker aircraft

Aerial refueling

Aerial refueling, also called air refueling, in-flight refueling , air-to-air refueling or tanking, is the process of transferring fuel from one aircraft to another during flight....

 is a long extendable metal arm that connects two aircraft

Aircraft

An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

for fuel transfer.