How many flights have taken off since 9/11, tons. So the odds of you dying in air travel are still astronomically small.
You are right on about Penn Station. I have felt it was a main target ever since 9/11. I come into Penn every day on NJ Transit trains and they do not check bags at all. This would be a major disruption to New York City's infrastructure. You have Amtrak coming in from all major cities, you have 5 major subway connections, New Jersey transit coming in from all points in NJ and you have the Long Island railroad - not to mention Madison Square Garden in the same building.