I know most of the talk at the time was about who the DOJ jet (N996GA) was about who it could be picking up when it was spotted in the UK on 21st March, and Q flagged it.
Now with the JA arrest and notice from the Police that there is an extradition request in place, it makes more sense that a senior DOJ official was travelling to the UK to negotiate this extradition with the UK and the Ecuadorian Embassy?