Originally Posted by
chevvron
FR24 does NOT show all traffic.
To be specific, there are two reasons why some traffic doesn't appear on FR24:
(a) It's not broadcasting position and it's in an area where FR24 can't do effective multilateration because of lack of coverage
(b) It's considered to be sensitive traffic and is voluntarily suppressed by FR24 even though its location is known.
In the linked video, NATS' Matthew Mills explains that the latter will also apply to Airspace Explorer.
More on the system here:
Six things you must try in NATS' new flight tracking app