Pemberton-Billing P.B.1
... that it is disputed whether or not the Pemberton-Billing P.B.1 ever flew?
... that it is disputed whether or not the <b id="mwEW4"><a href="./Pemberton-Billing_P.B.1" id="mwEW8" rel="mw:WikiLink" title="Pemberton-Billing P.B.1">Pemberton-Billing P.B.1</a></b> ever flew?