As much as I love Manchester (despite not being born Manc) and a great City it is, it is not a particular 'powerhouse' of anything since the cotton trade and the airport is publicly owned
Sorry Easyflyer, can't let that one slide under the radar !
Manchester is actually a major powerhouse in a number of areas and the airport activity reflects this, it is light years ahead of other "UK regional" cities, its just not universally recognised.
Of the top 20,000 companies in the UK 95% have their "second " HQ at Manchester. This growth is coupled to the level of academic research, it has largest and thee most popular campus in Europe with Manchester University amongst the top 100 in the world.
In terms of technology it is second only to London in terms of server capacity ! There are more data centre's here than the rest of the UK put together. Whilst some may question why the BBC are moving a signifciant part of their operation out of London, you cannot argue with the choice of location (yes OK its Salford, 2 miles from Manchester City Centre).
Retail - The major brands who choose to open second outlets outside London they almost always choose Manchester as the "proving" ground ! Next month The Avenue opens with tops brands normally found in Paris and Milan
Manchester United - arguably a worldwide draw, the largest football team on the planet apart from Real Madrid.
Stadia - MEN arena largest indoor arena outside London.
Property - Beetham Tower not exactly a beacon of iconic architecture, but functional, oversubscribed before it opened, and the largest residential tower in Europe !
Business, Art, Culture, Tourism, Sporting etc which ever you choose ..... those are the reasons WHY the airport is relatively successful !