HM Naval Base Clyde hosted United States Navy Admiral James G. Foggo on Wednesday, say the Ministry of Defence.
Aircraft carrier HMS Queen Elizabeth is expected to sail to the United States any day now for a series of trials with F-35 jets.
The debate over burden sharing within NATO is about as old as the alliance itself.
Coalition aircraft continued to strike Islamic State in designated parts of Syria and Iraq last week.
The US Air Force shared a draft request for proposal for the Light Attack Aircraft with Sierra Nevada/Embraer and Textron Aviation following the conclusion of the second phase of the Light Attack Experiment.