FareUpThere - Earn rewards for your feedback on flights
Glympse - Glympse is the easy way to safely share your location in realtime. No sign-up needed.
Skyscanner - Skyscanner.com compares over 1000 airlines to find you the cheapest airfares, fast.
Zenly - Zenly is a GPS tracker to locate your friends in realtime.
Eighty App - Convenient travel wishlist app with booking alerts
OwnTracks - Cross-platform location sharing