All screening equipment at the airport security checkpoint is safe for all travelers, including women who are pregnant. Watch this travel tips video if you have questions about the security screening process when traveling while pregnant.
How to Bench Press with proper form: setup on the bench, grab the bar, unrack it, lower it to your mid-chest and press it back up. Bench Press in the Power Rack for maximum safety. Set the safety pins at the proper height so they catch the weight if you fail to lift it.
But be sure to stay in a pain-free range of motion. If you have pain at the bottom of the push-up, place a foam roller under your chest and only lower down to a point where your chest makes contact with it. Finally, to be really honest, the bench press is NOT the only exercise that will build a big chest.