YOKOSUKA, Japan (AP) — The oldest active ship in the U.S. Navy, the USS Kitty Hawk aircraft carrier, made its final departure from Japan today to be decommissioned after nearly half a century of service.

The Kitty Hawk, with sailors lining its decks, pulled away from Yokosuka port just south of Tokyo to the cheers of hundreds of schoolchildren and the sounds of brass bands.

It flew the "Don't Tread on Me" flag, which designates it as the oldest ship in the Navy.

The Kitty Hawk, the last conventionally powered aircraft carrier in the Navy, is to be replaced later this summer by the USS George Washington, a nuclear-powered carrier.

After leaving Japan, the Kitty Hawk will make a stop at Pearl Harbor in Hawaii and then travel on to the Puget Sound Naval Shipyard in Bremerton, Washington, to be decommissioned.

The ship, commissioned in 1961, became the first forward-deployed aircraft carrier in the Navy when it was assigned to Japan in 1998. It has since made 20 deployments in the western Pacific and participated in Operation Enduring Freedom in Iraq.

"Since it arrived in August 1998, the Kitty Hawk has been a visible symbol of strength in a rapidly changing world," U.S. Ambassador to Tokyo Thomas Schieffer said. "Goodbye Kitty Hawk, hello George Washington."

The Kitty Hawk and its battle group are the centerpiece of the 7th Fleet, the largest in the Navy, with 40 to 50 ships, 120 aircraft and about 20,000 sailors and Marines. Roughly 21 of the ships are based in Japan and the Pacific island of Guam, while the others rotate out of ports in Hawaii and the U.S. West Coast.

Along with the other 7th Fleet ships, the battle group in Yokosuka, once a major Imperial Japanese Navy hub, has a huge area of responsibility — covering 52 million square miles of the Pacific and Indian oceans, from the international dateline to the east coast of Africa.

Japan's leadership strongly backs the U.S. military presence in the country, and says the more than 50,000 U.S. troops in Japan are a stabilizing force for all of Asia.

However, the replacement of the Kitty Hawk by a nuclear-powered ship is controversial among some here because of fears of an accident. Navy officials have stressed that the ship is safe, and pointed out that nuclear-powered submarines have long transited Yokosuka with no problems.

Concerns about the George Washington were raised again earlier this month when a fire on the ship left one sailor with minor burns and 23 others with heat stress.

Sailors extinguished the fire several hours after flames were spotted near the auxiliary boiler room and air conditioning and refrigeration space in the rear of the ship. The Navy said the fire spread through a passageway for cables.

The George Washington is scheduled to be based at Yokosuka starting in August.