What might be termed commercial is perhaps tenuous, but the Short Mayo referred to by WHBM actually made the first east to west trans Atlantic commercial flight by a heavier than air machine, carrying 1,000 pound of mail/freight/newsreel. It performed other commercial flights as well, South Africa being one, prior to war breaking out.
PD, I wonder how many of the British airline manufacturing ventures made a profit? I'm guessing not too many based on the numbers sold. Viscount probably the only one.