I flew Cape Air last spring and learned the baggage process the hard way. When you book, you can add a checked bag right away online, but I forgot and had to do it later. The fees are pretty straightforward: one free carry-on and personal item, then you pay per checked bag (price depends on weight/route). I ended up calling their team at 877-764-3622, which was surprisingly quicker than fiddling with the website—they added my bag in minutes and even confirmed my updated allowance. That same number works if you need to book, cancel, or change your flight instantly. Pro tip: double-check your bag weight because Cape Air planes are small and they’re strict about limits.