Sure. Everyone has every right to ask you to delete your photos, or to ask you to do anything else.

That part is tricky. Everyone has the right to call the police when they need police services, but no one can simply call the police and order them to have you push some buttons on your camera. What did you mean by this?

No, quite clearly, he did not have to do so.

No, anyone can ask you to do anything for any reason or none at all. Flight attendents are no exception to this.

First, could you explain what you mean by there being "a security issue"? I assume that by issue, you meant problem, but what is a security problem? Causing something to be less secure? What, the airplane? Like making it easier for a burglar to break in or for someone to fall out? Maybe by security you meant safety.

How could photographing anything that the entire plane of people can see possibly affect anyone's safety? Can capturing an image of parts of an airplane using an electronic device ever be any more cause for concern than simply looking at those parts and remembering them? Do you seriously think that taking a photo of something that thousands of people look at every day -- on or off a plane -- is worthy of any more attention than a bunch of people looking at that thing is?

I'd say that if it's part of an agreement you made with United, they'd be right in demanding that you delete the photos and/or not take them in the first place.

Would you be more or less irked by that then you would be if someone took your photo in the airport terminal without permission? Compared to on the street outside the terminal?

At the suggestion of TSA's blogger Bob Burns, I contacted 50 U.S. airports last spring to ask if they knew of any local policies prohibiting photography of things in airports that are visible from publicly-accessible areas of the airport. I documented every response here on Flyertalk.