I flew last month and wanted to bring a Greek yogurt with me for breakfast (early 6 am flight). Good thing I asked the TSA agent before I went through the security checkpoint because yogurt is considered a liquid and the Greek yogurt is higher than the oz allowed for carry-on. If you are bringing yogurt with you put it in a insulated lunch bag and in your checked luggage! I was able to bring the mozzarella cheese stick and quest bars in my carry on with me no problem. I also brought small individual packets of peanuts for my snack so I didn't get tempted by the airline snacks. The RTD protein shakes (Atkins) also had to go in my checked luggage.