In a chimney flue, a damper closes off the flue to keep the weather (and birds and other animals) out and warm or cool air in. This is usually done in the summer, but also sometimes in the winter between uses. In some cases, the damper may also be partly closed to help control the rate of combustion.
A little more detail will help us answer your question. If your snacks are pretzels, potato chips, dried fruit or other dry goods, you can take them in your carry-on or checked bag. Snack items that are liquids or gels, like pudding, jello or yogurt, etc., falls under the 3-1-1 rules for liquids for carry-on bags. They can be transported in checked bags.
If there's one thing people can agree on, it might be that airplane food isn't the best. Carrying your own food items on-board planes is allowed, with certain restrictions, so, to avoid another disappointing meal at 10,000 feet, or to get you through a flight where nothing is served, consider taking your own food. Leave sharp knives and forks behind, though; they won't be allowed through security.