Aireon's satellite constellation (Iridium Next) has actually been completed as of January of this year, and they state their systems would be operational Q1 2019. It is quite possible part or all of their hardware was collecting data today.They advertise an 'Alert' service that is free but still needs to be enrolled in by operators. I am curious if such data would be made available, either publicly or to the airline or investigators.
Their data would overlap with the ADS-B data collected by FR24, but was collected on superior receivers that are much less sensitive to terrain from their orbit, so more datapoints may well be available.