This one is quite a stretch but the livery has always been a favourite of mine - something about bold 50s/60's design does it for me. So let's assume -
* BA CityFlyer operate CRJ800s
* They painted one in a late 50s-mid 60s BEA livery ( like they did the A319 )
and here we are. I borrowed elements from the BAC 1-11 and the Trident liveries and had to make a few things up ( I must have gone through 5 different winglets ) but it suits this airframe surperbly. The nacelles on the CRJ are composites so I tried to make it look like they had silver paint or a silver coating rather than be bare metal, I think it worked to some degree or other. If not, please just suspend your disbelief a little...
Callsign is "FLYER" - if you want a pure BEA aircraft there is a zip file inside the livery folder which you can unzip in place, it'll remove any British Airways branding & change the callsign to the proper BEALINE. If it doesn't unzip, the aircraft.cfg goes in SimObjects/Airplanes/Aerosoft_CRJ_900_BEA and the dds ( texture ) files go in texture.BEA under that. I'd recommend using "BEELINE" if you use ingame ATC or it'll make some comical attempts at pronouncing it.
British European Airways ( not to be confused with the later British European which became Flybe ) were a nationally-owned company formed in 1946 to operate short-haul routes. By the early 1960s it'd become the biggest airline outside the US. In 1974 it merged with BOAC to become British Airways. BA Cityflyer grew out of the remnant of BA Connect ( originally Brymon Airways, bought out by BA ) which it didn't sell to Flybe, and now operates to a range of European destinations, so something of a spiritual successor.