In an alien world, much alike earth, exists a theropod-like aerial predator, slightly larger than a lion, which also hunts on land. The creature's eyes occupy around 30% of its face, for hunting both during the day and at night. Now as far as I am aware of, slit shaped pupils are great for hunting at both day and night and provide good depth perception, being common in ambush predators, but it's not as common in animals "far" from the ground, as we see in cats having slit pupils but most panthers having round ones. Would it be possible to have something akin to a slit shape on a flying creature (maybe something like a target shape?) or should I just stick with a round one?
Skimmers, which are real-life birds, have slit pupils.
Given their rarity, the evolutionary advantage of slit pupils seems pretty minor. The good news is that you can give your flying predator whatever eye type you like.
Having an aerial predator bigger than a lion may be more of an issue, don't sweat the small stuff...!