Can you bring food on a plane?

You cannot take home made food through customs into pretty well any country. Only packaged and sealer commercial foods.

you really should just call the airport and ask instead of letting everyone make wild guesses....but lets keep things simple yes, TSA is well aware of how much airlines charge to check a bag...for security reasons liquids of any kind must be in separate containers of no more then 3oz and should be packed kept in individual bags to protect your luggage if they leak. So again keeping things simple, your brownies are not a controlled substance and they are not liquid > 3 ounces, so yes you can carry it on.

Put it in your checked luggage. When filling out your declaration on the flight, make sure you mark the yes box that asks if you are bringing in food. If where you are going does not allow the brownies, you won't be in trouble. If your brownies have anything illegal in them, leave them at home. The dogs at the airports are very good at sniffing out drugs no matter what you do to disguise them.

I feel I should point out that brownies don't fool the drug sniffing dogs that are in all international airports. Just saying...

If you plan on consuming it all onboard, that's fine but if you intend to actually arrive with your food, that's a different issue.

You need to check with the customs of the country you're going to. Some countries prohibit the import of certain foods, especially unlabeled or otherwise foods that they don't know the contents.

It Depends on the Airline. It is better to ask the Airline through their hotline as policies vary from various companies.

You won't have any problem at all by bringing any food or drinks onboard the aircraft that you bought AFTER security. 

Just to clarify for other answerers and other people reading: You can bring food from home, as long as it is not soup or other liquid, and it will still pass through security! I used to bring my own food all the time, and TSA and other security are just as strict with Crew as they are with Passengers! 

You are not saying where you are going, but I would like to add that bringing food items into certain countries is illegal or subject to restrictions. This applies for South Africa, the UK, the US, and lots of other countries. So if you are flying international I would recommend you eat it on the plane or leave it behind when you disembark.

Yes you can - Some flights to don't serve or charge for food these days.

What I do, when I get past the security at my local airport, is go to Boots, and pick up a Meal Deal for about £3.

Brownies are allowed by current TSA regulations. They must be in a container or securely wrapped. If you carry them rather than place them in a checked bag, you must surrender them for x-ray screening.

Whether you can take food on board a flight depends on the airline involved. Some cut price airlines allow you to take food and water on board, but others don't. You'll need to check whether you can with the specific airline you're traveling on.