Apparently the publishing and events part of Flight retains the 'FlightGlobal' brand so the magazine is still Flight (can you still get it in Smiths?) while the information and consultancy part becomes Cirium. However, for certain market sectors the FlightGlobal brand 'Ascend' becomes 'Ascend by Cirium' ugh. No doubt Ascend by Cirium, in use, will immediately get shortened to just Ascend so no change there.
Over the last few years Flight has acquired a number of companies, Ascend, Innovator, Diio, FlightStats etc so the rational seems to be to bring them all together under a single brand. I would have thought that 'Flight' was a good brand and over 100 years old but maybe its not as well known in the US and/or too closely associated with the magazine. Ascend also seems to be well known in its market sectors but perhaps not so much in Innovator, Diio etc markets?