Question: Are there situations in which a pilot could/has to lower the landing gear during flight for reasons not directly connected to landing? (i.e., not part of the landing checklist)

Originally I thought I had seen some around the location indicated by the pin on the map below (17° 25' 30.093" N, 78° 32' 27.4734" E), in the evening time around 4:00 and the weather was clear.

[![Sighting location](https://i.stack.imgur.com/78nOO.jpg)](https://i.stack.imgur.com/78nOO.jpg)

Answer: 
I cannot imagine much need to lower the gear during flight, except perhaps if there was an issue. Also doing so mid flight would required restricting speed to the lower of Vlo (landing gear operating speed) or Vle (landing gear extended speed).

The actions that one takes that involve dropping the gear are usually part of some error handling procedure. These may be documented in operational manual or be something defined during training on the specific aircraft.

The one time I dropped gear in flight it was after one of the gear lights failed to turn off (indicating gear up and stowed) after retract. I slowed up to stay within the operational limits, dropped the gear and then retracted the gear. This time the gear light stayed off. After landing I checked the gear switches for a stuck piston or loose wire. I did not find anything and the problem never repeated.

If the problem had been something like a gear motor circuit breaker popping I would have reset the breaker ONCE. If the breaker popped again I would have cranked the gear down and left it down.
Sure it's a private ***jet***? Plenty of single-engine piston powered aircraft have fixed landing gear.

Most jets cruise at high altitudes, so if you can a) see the aircraft, b) identify it as non-commercial, c) notice the landing gear is down, and d) claim that it's not near an airfield then it's more likely that it is a 4-6 seat piston single with fixed gear. Cessna, Piper, Beechcraft have made thousands.

Addendum to edited question:
You say there are no airports *near by*. Possible there's one a little further away? Planes typically raise the gear as soon as they are off the runway, but they lower it 30km out. And that's 30km flying distance, not driving diatance.