These people will choose to use a shuttle service from the likes of LBA and connect at LHR rather than drive to MAN once R3 is built. People are already using the BA flights from LBA rather than going to MAN. Anyone that has had to slog over the M62 in winter in the early hours will know this is a preferred option.
That's an interesting assertion although it may well be partially correct.
Firstly, if you read the Leeds thread, you will see that LBA is not considered the most easily accessible of airports, especially in winter and with its overall weather record.
Secondly, there is actually quite a good train service from Leeds, Huddersfield and York direct to MAN which seem to do pretty good business, so driving across the M62 is not necessarily the only option.
Thirdly, MAN 's long haul passenger figures at the moment continue to grow, and I suspect a fair few come from Yorkshire despite the availability of shuttles to LHR from LBA.
All that said, I am a little concerned at the potential risks R3 at LHR would pose for MAN in terms of restricting growth or even reducing some long haul services or frequencies, unlike those who claim it would have no or negligible effect.
However, I don't see how you can assert MAN management "are so worried" about R3, as they have adopted a fairly restrained approach in public comment during the Davies Commission and in its aftermath to-date.