Snowflake ex-CPH, Germanwings, Germania Express, ex-various. Look at http://cheap0.com/total.php Zero-dark-thirty arrivals in some cases, at Sabiha airport (where?) which I gather is some distance from things.

Also cheap RTs from LGW on Czech, via PRG. We're looking at an open-jaw EDI-PRGx (nonstop - who knew?) -IST/PRGx-LGW (12 mo. limit, so works for XONEs) for something like US$350; a little more (but not much) than the LCCs. Plus we get 8 mid-day hours in PRG en route for a little touring around and a beer or three.