How may with guns.
On planes? Zero. Next question?
This is type of issue is exactly why I personally an such a stickler (read: "extremist" or "gun nut") in regards to the 2nd Amendment. As soon as We The People allow Congress, the President, the courts, or bureaucrats to whittle away at ANY of the amendments' protections, it only builds momentum. Government isn't too keen on voluntarily cede power or control once it's been established, and rights once lost won't be given back - they have to be taken back.
Either the Constitution in its entirety is the supreme law of the land or it isn't.
I propose a hybrid car that fetches breakfast for me before I leave for work in the morning.
There. I've done the hard part. The rest is just engineering, right?
Hmmm... maybe it could fly, too? Let's see how many other asinine pie-in-the-sky iterations can we make on an already terrible idea....
How exactly is a pro-life sentiment incongruent with civil liberties?
The question really boils down to whose rights should trump: mother to be or child to be. Pro-choicers usually rely upon corner case hypothetical situations in an attempt to justify their position, but that approach wholly ignores the civil liberty issue you bring up. Somehow it's a violation of civil liberties to insist the government step in to protect those who cant protect themselves? I'd wager you're a big fan of the government propping up unions to protect the helpless workers from big-bad-wolf corporations.
Before you throwing out the "fetus isn't a person" argument, think about it for a second; it's the same inane mental word gymnastics that allow people to convince themselves there is a difference between being "detained" and "arrested" (or being locked in a room from which you are unable to leave isn't REALLY even being "detained").
New systems generate new problems.