Gilles I agree on the Cityjet point.
Cityjet need to diversify their operations rather than just have their focus in London City as they have in the past. With Flybe about to offer increased competition there, the more they can grow elsewhere the better.
Cambridge does seem a bit if a strange choice, but good luck to them. It would be nice to see them bring a Fokker 50 to Luton. It would be the perfect sized plane for the route you mention all of which I genuinely feel could be successful at Luton in the future. It may be wishful thinking but here's hoping