http://www.flightradar24.com/

There is also a Android app for the same which gives you details of all the commercial air traffic around you
1. Details of flight number
2. Destination and origin
3. Route plotted on google map
4. Speed
5. Heading
6. Altitude
7. Live GPS coordinates
8. Radar ID
9. Squwak

The google paid version (Rs 500/- approx) on your Android mobile is even better you can scan them as a radar screen on your mobile camera view using the GPS and magnetometer of your mobile. It shows the details of the flight on camera view. it points to the exact direction and elevation of the flight with flight details.

how does the app get the atc data ?

Its just downloaded from ATC database updated by all airlines live on wordwide web over internet.

You need to have internet connection.

Build your own ground station to receive flight data directly from aircrafts using a USB ADS-B DVB-T SDR Radio dongle and Raspberry Pi.

http://uk.flightaware.com/adsb/piaware/build

But why do we hobbyist need it.

Its not that you need it absolutely. Just posted it as a cool thing to be done and challenge yourself. May be pick up a unique hobby like bird watching this can be Flight watching 

@rcrcnitesh
Nobody needs it.
99.99% of the population doesn't need model airplanes either.
But if you were to stumble on to that site (flightaware) you'd be amazed.
Does Mary Kom need to fight?

Subscribed.!! its my thing.

Ashok.P

Quote from: sundaram on October 21, 2014, 11:15:03 AM
Build your own ground station to receive flight data directly from aircrafts using a USB ADS-B DVB-T SDR Radio dongle and Raspberry Pi.

http://uk.flightaware.com/adsb/piaware/build

Did your Dongle caught so many ADS-B transmissions ? I tried on Laptop with the stock Whip antenna and got only 4-5 flights data ! What antenna are you using ?

No Ujjwana those images are straight from the Flight aware page not mine.