This is a long shot, but just posting here in case anyone knows of any products that would fit the bill.

My company flies tourists into a remote area with no mobile coverage. Wifi is currently not available at all but it may be possible to rig something up with one of the local companies that has a satellite connection.

I need a way to keep track of our passengers so that we can find them for the return flight. The whole land area would is a 1km triangle and pretty flat, so line of sight should not be an issue. Ideally the tracking system would show up on the pilot's phone with live data about where the passengers are.

Products I've looked at:
Bluetooth tiles (TrackR / Tile etc). These have a 50m range at best. Might work if we managed to get wifi around two+ locations in the area, and stash a phone at each to use the "CrowdLocate" that these products come with. Advantage is that they are very small and don't need recharging. Cost: $20-40 per unit (we would need ~30) plus getting wifi into the place.

Outdoor comms with location tethering (Gotenna, gotoky, Gotele, Sonnet) These have plenty of range. The ones without internal GPS tracking need to be paired with a smartphone app to share location so won't work. They can all be used by pilots to communicate with each other which is a plus. Gotele and Sonnet have internal GPS, but they are both very new products.

Pet/child trackers (Findster): virtually all of these require mobile coverage, but there are a few that don't, such as Findster. Findster has the range, but it is limited to 3 trackers per "guardian" clipped to pilot's belt. Findster was going to be my choice until I found out about that limitation.

RFID long range: expensive and maybe not possible to set up all the monitoring stations.

Satellite trackers (SPOT tracker): expensive and bulky, needs recharging quite often.

Vehicle GPS Trackers: bulky and usually rely on mobile coverage.

If anyone has solved a problem like this I'd love to hear about it!

Bullhorns