You can put a lock on your suitcase when flying to USA, but it's not required. The Transportation Security Administration (TSA) recommends that you use a TSA-approved lock to secure your luggage. If your luggage is selected for inspection, the TSA will use special tools to open the lock without damaging it. If you choose not to use a TSA-approved lock, the TSA may have to cut off your locked bag if it needs to be inspected.