They will shortly head on to Hawaii for a debriefing. US military authorities said the crew would be able to telephone their families, freshen up and eat before flying on to Hawaii.

Please convey to the Chinese people and to the family of pilot Wang Wei that we are very sorry for their loss

US letter of apology

China allowed them to leave after the US expressed regret over the loss of a Chinese fighter pilot involved in a mid-air collision with the US plane.

In a brief statement on Wednesday, US President George W Bush said the American people joined him in "sorrow for the loss of life of the Chinese pilot".

Mr Bush did not apologise for the accident itself or admit US responsibility for it.

Click here to see the crew's route home

The Chinese decision to release the US crew follows the delivery of a letter to the Chinese Foreign Ministry from the American ambassador, in which the US Government said it was "very sorry" about some aspects of the incident.

The letter conveyed US regret for landing on Chinese soil without permission.

It proposed a meeting between US and Chinese representatives on 18 April to discuss issues related to the incident.

Not the end

Timeline of the dispute

1 April: Collision forces US spy plane to land on China's Hainan island; China blames US 3 April: US diplomat holds first of five meetings with crew 4 April: Chinese President Jiang Zemin personally demands US apology 8 April: US Secretary of State Colin Powell says he is "sorry" for the loss of the Chinese pilot 11 April: China announces crew will be released 12 April: Crew flies out of China

But while the crew's ordeal may be over, observers say this is unlikely to be the end of the dispute. There is no mention in the Chinese statements about the spy plane itself.

Chinese Premier Zhu Rongji, quoted by the official Xinhua news told the UN: "All responsibilities for the incident lie with the US side."

Correspondents say China is likely to press hard for restrictions on US surveillance flights over or near Chinese territory.

Beijing is also likely to put pressure on the US on bilateral concerns such as trade and entry to the World Trade Organisation.

Preparing public opinion

On Wednesday, China's state-run media began reporting comments made by US Secretary of State Colin Powell three days ago, in which he expressed sorrow for last week's collision.

The change in the character of the Chinese media reporting, correspondents say, was preparing public opinion for an announcement that a deal to return the crew of the US spy plane had been reached.

Mr Bush expressed sorrow but did not admit guilt

Correspondents say the precise wording, and the extent of regret, offered by the US in writing was crucial because Chinese leaders needed something to show the public, whose sense of outrage over the incident has been heightened by anti-US rhetoric in state media.

They also say Chinese officials appear to be preparing to announce the death of the missing airman, Wang Wei.

The announcement of the pilot's death and the abandonment of a massive search for him is being seen as a vital part of bringing this dispute towards a conclusion.

State media have lionised the pilot as a patriot who crashed defending his country. Reports say more than 1,000 military and civilian vessels have joined the search for him.