BAE Systems chief executive Mike Turner, along with a senior colleague, has been briefly detained in the US upon landing.
Following the 20 minute delay, the two executives were not prohibited from entering the United States.
The US Department of Justice (DoJ) has now made contact with Home Office to formally ask for UK assistance in the American BAE investigation.
“The company has been and continues to be in discussion with the DoJ concerning the subpoenas served in the course of its investigation,” said a BAE Systems statement.
