I think elves should have Pegasus riders as well as hippogriph riders just make the Pegasus rider be like the Griffin rider stat wise and the hippogriph be like the drake knight stat wise. This is not saying every race should have two knight flyers each but the fact that elves could need these two with the addition of new terrain tiles e.g. Lava, chasim.
I believe it should probably be a unit based on mobility and with a good damage. It shouldn't be too tanky tough.
I also things that it should go to humans because they are the race with less fantasy units and the creature itself comes from ancient mythology as a divine mount for human heroes
Age of Fantasy design leader