Easy. The key you're given is only valid for the country the plane is over, and you rotate keys on a regular basis without repeating (and get your key on entry to a particular country/block of countries like the EU). That way, only planes which have already been authorized to go over a particular country's airspace can get keys. The keys don't have to be in the public hands, and you could even have a few hour grace period for transitioning keys so that the planes that were still in the air when the key changed aren't immediately flagged as using an illegal encryption key.
To be honest, it's a surprise that they don't actually do something like this. You still would know that there's a plane there when it responds back, but at least you can't get anything from it without knowing the key being used at that particular time (and leaking keys would only be valid for a limited period of time, which would make it so that they could just change what key to use for a particular interval when they know in advance that their list has been compromised).
Uh... wrong. Even if you tab, it won't indent properly when displayed using other spacing patterns. For instance, if you are lining up some statements that run over the line to make the code easier to read (which is a perfectly acceptable style), then different tab indents could screw that up. Using tabbing to just mask for indenting with spaces isn't a real solution to code indenting because of this, since you're still relying on a set tab spacing anyways in order to make your code readable, even if you don't think you are.
Because of this, what you're saying doesn't make a lot of sense to begin with, and it doesn't pay to try to trivialize the whole spacing debate. In any case, indenting with spaces removes ambiguity in how your code should be indented that tabbing introduces. If you seriously don't think that this is an issue, then you should seriously take a closer look at some lines of code which run over a line. If you've never had this problem, then you've never really done any serious programming before, and shouldn't really be commenting on something which you aren't familiar with.
As a programmer, I could really care less how many spaces a tab represents, or if someone uses tabs vs. spaces, but I do want to see consistency in its use within the bundle of code that I have to work on or consult, since having to switch back and forth for code spacing is going to be a huge drain on readability. And, like I stated before, just telling people to use ambiguous tabs over spaces without a tab to space convention already specified within a style document for your project doesn't do much more than to make the person viewing the code guess how many spaces their tabs represent. It may not sound like a big deal to you, but it can be a big headache when you have to continually switch back and forth between different tab spacing defines because different people like you assumed that a tab will look the same for everyone no matter how many spaces are used. Because of this, I would much rather prefer to define how many spaces a tab should represent in the code style documents for languages which have tabs as part of their syntax (like Python), and unambiguous spaces for everything else, so that I don't have to either guess at what sort of spacing the person used, or to read more style documents than I have to (most are designed rather well so that you can infer the style from code you've already seen. I personally would much rather not have to consult a style document unless I reach a case that seems ambiguous to me. That way, I can focus more on coding what I need to, rather than just reading every piece of documentation that comes my way.)
Arithmetic is being able to count up to twenty without taking off your shoes. -- Mickey Mouse