This is my first post so please be gentle!
I had the chance to fly duo very shortly before its demise and must say what great customer service it provided. Complimentary meals and great service from the cabin staff. It was like flying business class but we'd only paid an economy class fare. Perhaps this contributed to its downfall?
Through work, I got to know someone in their sales department. Apparently, BA gave duo a seriously hard time on the MXP and STR routes although others, like LYS and TXL, were growing and were getting to be reasonably successful. Certainly when I flew with them to LYS, I remember both flights being fairly full although I accept that is no indicator of a more general pattern.
I seem to remember that they were planning on obtaining 3 SAAB 2000s to replace the CRJ-200s shortly before they went under as a means of operating more fuel efficient aircraft. I also seem to remember that they had 3 new routes in the pipeline that I don't think they ever did operate in fact, to Bordeaux, Shannon and Pisa. I think they were due to commence with the summer timetable in 2004. I presume in the end, Bordeaux has worked as a destination from BHX given baby's operation of it, Shannon has been operated on and off over the years but who knows if Pisa would have worked?
As has been said, the advertising was odd. Park benches and ducks did not exactly lead to people remembering the name "duo airways". Also, for an airline that aimed to sell tickets just through its website, the site was hardly well promoted either. And I also thought, personally, that a few of its destinations - certainly from BHX - were perhaps optimistic - Helsinki, for instance?
A great shame it failed, in my view.
Just a few thoughts....