I had Joust in mind, but with the 48px high screen and no color it is going to be hard to make. We could technically make the player(s) white, and the other birds gray with a white lance, but there would be no way to differentiate between the types of enemies. Also, vertical scrolling would probably be needed... which makes flying upward quite a hazard. With birds and knights as small as 8px, it means you can fit only 6 vertically in a screen, that's not a lot of room to maneuver.
Doable, but quite a challenge really. We might have to resort to a simplified field, with fewer platforms, and really tiny birds that would not look much like birds with a knight on them.
Mabye something like this (black/white knight & bird) with a bit of scrolling.. You could also modify the gameplay a bit (like Glypha for the good old Macintosh).