RAF FAIRFORD, England (Reuters) - U.S. Air Force Chief of Staff David Goldfein on Friday said he was concerned about a delay in Boeing Co's $49 billion KC-46A refueling tanker program but remained confident that the company would be able to resolve the issue.

The Air Force last month said it would seek compensation from Boeing for a five-month delay in delivering the KC-46A Pegasus tanker.

Boeing and the Air Force announced in May that delivery of the first batch of 18 tankers would be pushed back to January 2018 from a previous deadline of August 2017, and that the planes would lack some capability until October 2018.

(Reporting by Andrea Shalal; editing by Jason Neely)