The Navy's largest ships are aircraft carriers. Today's carriers are about 1,000 feet long and carry hundreds of plane and helicopters. Airplanes take off and land on large, flat flight decks where many sailors work together to control the traffic. These ships are airports at sea. Each carrier is a floating community where about 5,000 sailors work, eat, and sleep together for months at a time. Aircraft carriers launch, recover, and repair airplanes and helicopters. Carriers protect the fleet and are used as an offensive force against an enemy.