Does Daylight Saving Time affect the flight time? Say an example flight FRA-LHR, was scheduled say 9am every day. Now will that flight be then moved to 10am once the change to DST happens or will it remain at 9am?  

I would expect the flight times schedule to remain the same i.e. the daily morning FRA to LHR flight will be always departing at 9am (independent of summer/winter time changes). My knowledge in this area is limited so I wanted to know what the experts on this site say. 

My question is more directed at the flight schedules i.e. the daily flight scheduled at 9am for example - does it undergo schedule change and is moved to 8am/10am or is this time fixed (underlying assumption being: in general a flight is scheduled for a certain time to meet a demand, so moving the local time is not necessarily feasible).
It will affect scheduled flight times the same way it will affect your favorite TV show's air time.

i.e. it won't*

It will affect apparent flight duration if the departure and arrival airports switch to DST on different days of the year, but actual time in the air will remain the same.

* The caveat for that is if you happen to be in an area that A) does not switch to DST and B) your favorite TV show happens to be broadcast from an area that does switch to DST. (This situation happened every year in Indiana for many years until IN joined the 19th** century and switched to DST in the summer.)

** Yes I know that DST was a 20th century invention, it's just that Indiana is a bit behind the times...