Anti-Missle Technology on Planes?

I think it would be extremely expensive and since this is not a common issue then it wouldn't be of much use. But who knows, maybe this becomes a more accessible idea if something like this happen again.

No. Like anything else with war machines, for every defensive measure, there will be an offense one created to counter it. The cycle is never ending. This cost would be prohibitively expensive and the costs would only be passed onto the consumer--killing an already fragile industry. Further, missiles can be infrared, radar, or laser guided. Lasers, well, we can't even stop idiots from shining those at airplanes anyhow so forget defeating missiles guided by them. Infrared, you'd have to add flares as countermeasures--and dropping those on nearby homes and businesses may defeat the threat, but add another if the aircraft was on takeoff or departure. Radar jamming would be impractical since those systems are needed for atc purposes...blah blah blah blah blah. There's going to be another time where an airliner is shot down again. It will be sad. But do we forever live our lives in fear of the oh so minuscule possibility that it may be something that we experience first hand? Although, perhaps we just turn the old F-14 fleet into single passenger airliners and have a much better chance at overcoming a missile attack.

No - it makes them more of a target, plus the extra weight and composure of the flight crew will change dramatically. Better to have fighter escorts like they did in the days and months after 911. I'd feel safer and so would my pax.

This technology exists and is in use in selected high risk flights. After the Mombasa attacks in 2002 the use of this system become more widespread. Here is a good summary from Wiki:
http://en.wikipedia.org/wiki/Flight_Guard

The "what ifs" never end. Everybody dies. Fly near a war zone and it could come sooner. You can fix stupid. Suit yourself as to who is the stupid side.