Originally Posted by
IsleOfMan
The geared turbo-fan is probably the next big fuel-savings development and will likely be part of the CFM LEAP56 in the Boeing Y1 (B737-NG replacement study) or Airbus NSR (A320 replacement study).
Geared turbofan is already in use. Bring Another Engine 146. Which, for some reason, does not seem to be quite as popular as B737, A320 or Avro RJ.