INFOdocket co-founder Gary Price has written a roundup of several flight tracking apps and web sites that provide access to real time info. The post was published on Search Engine Land (where Gary is a contributing editor).
Some of the apps/sites are fairly new while others are old favorites including a look at apps and a web site to track European and Asian flights and a site to listen to live air-to-ground pilot/air traffic control conversations streamed (and archived) on the web. Many of the sources are free or have free trial versions available.
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Another recent article that Gary wrote for SEL.