TSA Security Directive SD-1544–09-06

Not that its very likely in the USA; with a few exceptions rail service is abysmal. It took me 48 hours to travel from Nevada to Chicago last time I took the train, what with mechanical breakdowns and other unexplained delays. Lost my luggage too. Never again.

Bombs in london and madrid caused hundreds of lives lost or serious injuries, bombs in the pakistan/india region often claim thousands.

The threat (as also mentioned here) is that a hijacked plane is, in reality, a massive missile and, to use the phrase, a true weapon of mass destruction. This however was resolved after 9/11 with new cockpit procedures and more alert passengers. (c.f. Bruce Schneier's blog for more)

At the Paris side, I was again approached by staff, this time offering me a Halal meal...

Passenger aircraft may be uniquely suited to inane security theatre. They're already so inefficient and uncomfortable that it's relatively easy to get away with piling on additional inefficiency and discomfort. And the problem of securing them feels almost tractable -- they're only vulnerable at the start and end of the trip [1], they have very limited entrances and exits, they carry so little stuff that you feel as if you actually have a chance of screening it all. [2] The problem with security theatre on trains and buses, to say nothing of ships, is that you just can't make it plausible without making it so expensive that you might as well just shut it down. Theatre is no good if the audience can't suspend disbelief.

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[1] Well, technically, there are surface-to-air missiles. But somehow those are easy to handwave away. Theatre is a mysterious business.

[2] You probably don't, of course, but reality is not at issue here.

(I once was trying to book a flight from Kansas City to Portland, and -- I kid you not -- one suggested route was through Atlanta)

On the other hand, it doesn't exist, and would be crazy expensive.

My point I suppose was that flight attendants are in a lot of cases not going to be able to physically enforce their will on passengers. This is where other passengers step in, they are the ones who will come to the aid of the flight attendant to restore the peace. This doesn't mean that everyone will be throwing their own judgement out the window if someone has to use the restroom or complains about having to put their book away.

It should go without saying though that reactions will seriously depend on the situation.

First, if you're in the air, you have line of sight to a lot more cell sites than you normally would. While there might be a couple sites at any give point that are a similar signal strength to you, here there could be hundreds. Basically, cellular wireless is based off the idea that your transmission only goes so far and therefore they can re-use the same spectrum in different locations (or, in the case of CDMA systems, not have every code talking over each other, but rather have a limited number of voices screaming). Being on a plane violates that. With a CDMA system, you'd either be drowned out by closer signals or you'd be causing a ton of interference for all towers within range and it'd be a lot of cell sites. With a TDMA system, you'd be transmitting on a frequency/time-slot that would be re-used on another tower that could similarly hear you. To explain that a bit more: in real life if you have:

  Tower FreqA :: Tower FreqB :: Tower FreqC :: Tower FreqA

Likewise, you're travelling at (potentially) 500 miles per hour. Travelling at 60MPH, you'll likely need a new cell site every few minutes (depending on geography and the like). At 500MPH, you could be getting new sites more often than not. Combined with the fact that you'd be in "range" of so many sites as noted above, it would become difficult for the network to determine which site you should be transmitting to/from.

And that is important. Cellular wireless only works because the same finite bandwidth can be reused since you aren't using that bandwidth in all locations.

So, unless microcells are used on the plane itself, wireless service is a terrible idea in the sky. A microcell in the plane would get the phone to transmit at a very low power (therefore not interfering with customers on the ground) and the cell site would be a constant distance from you. It's why even in countries where the aviation folk are moving toward cell phones on planes, they're doing so through microcells.

I'm not saying that it would't work. I haven't studied it, but it wouldn't be a wonderful experience and would cause havoc for the network.

EDIT: It seems that it's an FCC (in addition to FAA?) prohibition in the US (http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft#USA_C...). The article on Wikipedia also mentions airlines installing microcells (although not by name) to allow people to call on planes.

For example: http://www.af.mil/news/story.asp?id=123149266

It would be pretty easy to slip a gps antenna behind the shade before you closed it as well.

Passengers, beyond curiosity, have very little use for GPS during a flight. When I'm on a plane I could really care less what my location is. I'm more concerned with how much longer I have to wait before arriving at my destination.

The parts of the security directive that bother me most are the restrictions on access to carry-on belongings and items on your lap and not being able to get up from the seat.

You're right that an attacker probably wouldn't back out just because the attack wouldn't be maximally effective, but the result would still be reduced casualties. Ideally, you want to prevent all attacks, but even when you can't the next best thing is to reduce the severity.

Now, that doesn't mean to say that you couldn't hide a bag onboard with such a device, and then make some kind of excuse that you have to go back to your office because there's some kind of emergency, and you won't be taking the flight after all. But then, you'll have had to somehow get your device into the sterile area (requiring accomplices who work there, or some surprisingly good luck getting through the x-ray scanners and explosive detection machines).

In other words, the security we had pre 9/11, with a little bit of modernizing, does the job fine. The rest of it (shoes, liquids etc) are really just theatre.

This isn't fool proof but the FAA policy that my dad experienced years ago was that the passenger was dissuaded from leaving, the captain came out, and he was told that if he exits the plane they have to sweep it and because of that he'd be denied reentry. Passenger insisted. Argued a bit.

Long story short, the passengers all had to disembark with their luggage and go back through security screening. And the flight crew presumably did their standard pre-boarding sweep.

This was, oh, 2002 or so. I wouldn't be surprised if they even let you off the plane anymore, at least not until the 3-hours are up that the new regs mandate.

And similarly, there has long been double-checks to make sure that no checked luggage is on a flight that isn't matched to a passenger. My understanding is that luggage that is freight checked (like, they lose your luggage and throw it on a later flight to get it to you) has to be more thoroughly screened.

You don't care about the death toll, you just care about the fear.