Puppycow
Penultimate Amazing
It's been a while since I was in the Navy but I think I still remember the basic rules for saluting.
1) You are only supposed to salute when "covered", i.e., when wearing your cover, which is what we call the hat. You only wear your cover when outdoors, and when in uniform, you must also have your cover on when outdoors. You never salute when wearing civilian clothes. Nor do you salute somebody who is not in uniform.
Presidents don't generally wear hats or covers either indoors or outdoors, so really they shouldn't be saluting or returning salutes (since nobody is above the president, there is no one for him to salute, but it's kind of awkward when you are saluted to not return a salute). The person saluting (the lower-ranked person) is not supposed to drop the salute until it is returned. Which is another reason why it is kind of awkward to not return a salute. So I guess for presidents and nobody else, you can return a salute without a cover or a uniform.
1) You are only supposed to salute when "covered", i.e., when wearing your cover, which is what we call the hat. You only wear your cover when outdoors, and when in uniform, you must also have your cover on when outdoors. You never salute when wearing civilian clothes. Nor do you salute somebody who is not in uniform.
Presidents don't generally wear hats or covers either indoors or outdoors, so really they shouldn't be saluting or returning salutes (since nobody is above the president, there is no one for him to salute, but it's kind of awkward when you are saluted to not return a salute). The person saluting (the lower-ranked person) is not supposed to drop the salute until it is returned. Which is another reason why it is kind of awkward to not return a salute. So I guess for presidents and nobody else, you can return a salute without a cover or a uniform.