RE: Public transport
I've said it before and I'll say it again. It's actually very difficult to get passengers to arrive via public transport. MAN is still a very leisure airport with the once or twice a year brigade travelling on their hard earned holiday. Suggest travelling their by train and they'll be "sod that, we're getting a taxi". It's very hard to compete with travelling door to door. For many of those people the holiday still begins at the airport, they don't want the faff (or perceived faff) of getting a train, they'd rather treat themselves to a taxi or hotel/car parking. Plus, when travelling in a family or group, a taxi/mini bus us far more economical in most cases.
You do see a difference in travelling habits between flights however. Many tend to use the train on business/city route pairs when passengers also tend to fly more frequently.