Yes, you are absolutely allowed to pack crisps (potato chips) in your hand luggage when flying. Since they are a solid food item, they are not subject to the 100ml liquid restrictions that apply to gels, pastes, or drinks. However, there are a few practical "travel hacks" to consider when flying with crisps. First, be aware that air pressure changes in the cabin can cause the sealed bags to expand significantly, sometimes even popping if they were packed at a very low altitude. To prevent this (and to save space), some travelers poke a tiny pinhole in the bag and squeeze the air out, though this can lead to stale crisps. Second, crisps are fragile; if you stuff them into a crowded overhead bin, you will likely end up with a bag of crumbs. It is usually better to place them in your "personal item" under the seat in front of you. Finally, if you are flying internationally, you should technically consume them before landing or check local customs laws, although processed, cooked snacks like crisps are rarely an issue compared to fresh fruit or meat.