Landing Signal Officers (LSOs) played a crucial role in aircraft carrier operations. During World War II, available radios, unlike the ones from the modern day, were primitive and could only send Morse code—a type of communication not very well-equipped to send urgent messages to pilots quickly and clearly. In their place, LSOs would stand at a very exposed position and use a pair of paddles (pictured above) to guide tens of thousands of pilots to make carrier landings safely.