A casual jacket is generally a shorter piece of outerwear that works for any kind of outfit, rather than favouring a formal style.
A smart casual jacket is a comfortable inbetween from a formal jacket and a more casual style - generally this will be made of wool or tweed fabrics, with a shorter body.
However you like - casual jackets will match with any outfit or wardrobe by design.
A casual jacket should fit without restricting movement - being soft and comfortable with plenty of room.
For a classic mod look, the best match with a bomber jacket is an Oxford shirt and chinos, or some skinny jeans. There’s no better way to recapture the golden age of menswear!