Yes and No. According to the TSA “Body armor is generally allowed” in a carry-on or a checked back, however, officers reserve “Final discretion.” You may need to remove the insert and place it in a separate bin during security checks. Remember, while the inserts are legal, any attempt to use them in a threatening manner would still be illegal. It's also essential to verify the regulations of your specific airline and the local laws of your destination, as some regions may have restrictions on body armor.