U.S. Navy LT. CMDR. Chris Pace, Dental Officer performs a jaw tumor biopsy on a patient aboard the U.S. Navy Aircraft Carrier USS NIMITZ (CVN 68). The USS NIMITZ (CVN 68) is currently underway off the coast of Calif., conducting sea trials after successfully completing a six-month Planned Incremental Availability period. Sept. 1, 2006. (U.S. Navy photo by Mass Communication SPECIALIST SEAMAN Emily Stroia) (Released)

Aircraft carriers are warships that act as airbases for carrier-based aircraft. In the United States Navy, these consist of ships commissioned with hull classification symbols CV (aircraft carrier), CVA (attack aircraft carrier), CVB (large aircraft carrier), CVL (light aircraft carrier), CVN (aircraft carrier (nuclear propulsion) and CVAN (attack aircraft carrier (nuclear propulsion). The first aircraft carrier commissioned into the United States Navy was USS Langley (CV-1) on 20 March 1922.