An HB-350B Esquilo (Brazilian navy version of the French Ecureuil) helicopter, left, and an SH-3D Sea King helicopter are checked out in front of the island of the Brazilian aircraft carrier MINAS GERAIS (A 11) during the hemispheric naval exercise UNITAS XXV. The silver anniversary hemispheric naval exercise involving Brazil, Chile, Colombia, Ecuador, Peru, the United States, Uruguay and Venezuela

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.