When you look on an airport activity map, how come some flights are shown in Green and some in light blue? and I have noticed that some of the track lines don’t have a flight ID on them.
Bruce
Hi, Bruce. Flights in blue are to/from the airport being viewed. Flights in green are transitioning that airspace to and from other airports.
As far as the missing data block, the FAQ explains:
Why do airplanes only sometimes have the “data block” next to them with flight information?
Due to limited screen and resolution real estate, FlightAware Maps has to selectively “de-clutter” the maps so that data blocks aren’t overlapping each other. If you’re tracking a single flight and it’s near the origin or destination airport, it might not have a data block to ensure that the airport code itself isn’t blocked. On the ATC-style displays with many flights, often times there are so many flights in limited space that it’s not possible to display data blocks for all of them. In future iterations of the software, a more powerful zoom feature will alleviate this problem.
Are you clicking on the map to view the larger image? It’s less of a problem in the 800x600 image.
ok thanks. Yeah I can see some without ID’s on the big size map but maybe its because the flight track is too close to another one or the airport.
I was SO close to posting this same question, but I found it. 
I still have a problem with this feature of the system. If I type in an airport identifier like MSN, it shows all the over flights in green, and all the arrival/departures in blue. That part is great, but why is it showing 50 data blocks for the green over flights, and omitting the 3 blue ones for the airport Im tracking. If anything, there should be an algorithm that ensures no BLUE data blocks are dropped before any GREEN ones.