A British F35 jet from the British flagship aircraft carrier has crashed into the Mediterranean during the flight, and the pilot has thrown out in the first such incident that hit HMS Queen Elizabeth.
Hostile action is not believed to have been involved.
An investigation is likely to focus on potential technical or human error.
A Defense Department spokesman said: “A British F35 pilot from HMS Queen Elizabeth was thrown out during routine flight operations in the Mediterranean this morning.
“The pilot has been returned safely to the ship and an investigation has begun, so it would be inappropriate to comment further at this time.”
The next generation of the £ 100 million RAF F35 jet is believed to be in the sea and has not yet been restored.
Eight British F35 jets are on the airline, along with 10 US F35s. They are the B variant of the Lockheed Martin jet, which can take off at short distances and land on the aircraft.
HMS Queen Elizabeth returns to the UK after more than seven months at sea on a maiden voyage to the Far East and back.
The incident took place around 10am UK time in international waters. No other vessels or aircraft were involved.
A comprehensive military air survey will be conducted immediately.
All other F35 operational and training flights continue.