I want to thank everyone who took the time to reply and offer suggestions. I am now considering the small, crossbody type bag work under a jacket as an option while flying. Oldpenny, your blazers sound perfect.
I confess that I did use my quest as an opportunity to indulge myself and buy a Ted Baker men's suit jacket. I love the lines, fabrics and linings that Ted Baker uses. I found an ideal one on e-bay and am waiting for it to arrive. It will first go to the cleaners, then to the tailor to be fitted. If this works it will be ideal for those occasional flights that go from airport directly to office.
It helps that I only need interior pocket space for my passport and slim travel wallet. We'll see how this all works out.